Editor: quick fixes, completion, navigation while typing, and split-pane drag (#109)

* feat(editor): Drag tabs and files between split panes

HTML5 drag and drop never reaches the webview while native file drop is
enabled, so tab, project-file and changelist drags did nothing. They now
run on pointer events:

- Drag an editor tab onto another pane, or onto a pane's edge to split it.
- Drag files from the Project view into an editor pane (center opens them
  there, an edge opens them in a new split).
- Drag files between changelists in the Commit view.
- "Drag-and-drop with Alt pressed only" applies to tabs and stripe buttons.

* fix(lsp): Deliver server settings and start servers on a supported JDK

- workspace/configuration answers a server's own section (basedpyright)
  from its settings block; basedpyright runs in "standard" mode and keeps
  auto search paths on, so `src/` layouts resolve from `tests/`.
- jdtls: formatting follows the editor indent, calls complete without
  guessed arguments, and JDK internals stay out of completion.
- `max-java` in a language server config picks an installed JDK no newer
  than that (kotlin-language-server fails on JDK 25).
- Server initialization may take up to 5 minutes (first Gradle import).
- `lsp_resend_diagnostics` re-emits stored diagnostics after a reload.
- Spelling only checks declared names (not called methods like
  `substring`) and accepts plurals of known software terms.

* feat(editor): Quick fixes, completion and navigation while typing

Quick fixes
- Errors get a red quick-fix bulb; Apply Quick Fix (⌥⇧↵) fixes the most
  severe problem at the caret, and the error hover offers the fix directly.
- Code generated by a code action is re-indented to the file's style.
- Python: Implement abstract methods (⌃I or the bulb) from the bases.
- Duplicate code actions are listed once.

Completion
- Overloads sharing a name, and a name importable from several modules,
  are no longer merged into one entry.
- Auto-import entries show the module they import from.
- Call snippets without a stop (`new ArrayList<>()`) leave the caret inside
  the parentheses with parameter info, or past them when nothing takes
  arguments; parameter info also opens after server call snippets.
- The selected item is resolved ahead of acceptance, so its auto-import
  is applied (rust-analyzer).

Navigation and diagnostics
- Language server requests wait for pending edits, so Go to Declaration
  right after typing answers for the current text; an empty answer right
  after an edit is retried while the server catches up.
- Diagnostics come back after a window reload; error underlines stay
  visible under typo / unused highlighting.
- Implementation gutter markers no longer refresh in a loop while the
  server reports progress.
- A missing alternative server no longer shows as a server error.

* chore(lint): Skip agent worktrees under .claude

* fix(editor): Skip cancelled LSP requests and limit generated-code reformat

- Requests cancelled while waiting for pending edits are not sent.
- Code generated by an action is reformatted per changed hunk, so an added
  import doesn't reformat the code between it and the generated lines.
- A long busy spell caused by a settle refresh re-runs it only once.
- Files dropped on a file row of another changelist move to that changelist.
- Python Implement methods: a nested class without bases ends the lookup,
  class bodies continue through unindented string lines, and
  `@abstractproperty` stubs become `@property`.
- Resend diagnostics goes through the host ops, and custom servers get
  `max_java`.

* fix(editor): Rank the exact type first in Java constructor completion

jdtls appends the call or body to filterText (`String(${0})`); matching
on the label instead lets typing `String` rank `String` above
`StringBuilder` and the other types sharing its sort text.

* fix(editor): List identical completion items once

kotlin-language-server repeats a class once per classpath entry declaring
it, so `String()` and `String` were listed three times each.

* fix(editor): Keep the internal cancellation message out of the UI text catalog

src/features/code-insight/ServerStatus.tsx

@@ -5,7 +5,7 @@ import { getAction, executeAction } from "@/platform/actions";
 import { BarButton, Button, IconButton, Popup, T } from "@/ui";
 import { downloadJdkActions } from "@/platform/jdk";
 import { relativePath, useProject } from "@/platform/project";
-import { STATUS_LABEL, restartServer, serversSummary, useServers } from "./servers";
+import { STATUS_LABEL, restartServer, servedByOther, serversSummary, useServers } from "./servers";
 import styles from "./ServerStatus.module.css";
 import { tx } from "@/platform/i18n";
 
@@ -49,7 +49,10 @@ export function ServerStatus() {
             return (
               <div key={s.id} className={styles.server}>
                 <div className={styles.line}>
-                  <span className={clsx(styles.dot, styles[toneOf(s.status)])} aria-hidden />
+                  <span
+                    className={clsx(styles.dot, styles[s.status === "missing" && servedByOther(s, servers) ? "idle" : toneOf(s.status)])}
+                    aria-hidden
+                  />
                   <span className={styles.name}>{s.name}</span>
                   <span className={styles.status}>{STATUS_LABEL[s.status]}</span>
                   <span className={styles.spacer} />

src/features/code-insight/servers.test.ts

@@ -20,7 +20,7 @@ vi.mock("@/platform/ipc", async (importOriginal) => {
 
 const { emitLocalIdeEvent } = await import("@/platform/ipc");
 const { useProject } = await import("@/platform/project");
-const { installServerEvents, useServers } = await import("./servers");
+const { installServerEvents, serversSummary, useServers } = await import("./servers");
 
 describe("server status", () => {
   let dispose = () => {};
@@ -40,3 +40,18 @@ describe("server status", () => {
     expect(useServers.getState().servers.get(id)).toMatchObject({ status: "missing", message: "install jdtls" });
   });
 });
+
+describe("serversSummary", () => {
+  const entry = (id: number, name: string, status: ServerInfo["status"]) => ({
+    id: id as ServerId,
+    name,
+    status,
+    message: null,
+    languages: ["typescript"],
+    root: "/p",
+  });
+  it("doesn't flag a missing server whose languages another one serves", () => {
+    expect(serversSummary([entry(1, "vtsls", "missing"), entry(2, "typescript-language-server", "ready")])?.tone).toBe("ok");
+    expect(serversSummary([entry(1, "vtsls", "missing")])?.tone).toBe("error");
+  });
+});

src/features/code-insight/servers.ts

@@ -129,10 +129,23 @@ export const STATUS_LABEL: Record<ServerStatus, string> = {
   misconfigured: "Not started",
 };
 
+/**
+ * A missing server whose languages another installed one serves (vtsls missing,
+ * typescript-language-server running as its fallback) is not a problem.
+ */
+export function servedByOther(server: ServerEntry, servers: readonly ServerEntry[]): boolean {
+  return (
+    server.languages.length > 0 &&
+    server.languages.every((l) => servers.some((o) => o !== server && o.status !== "missing" && o.languages.includes(l)))
+  );
+}
+
 /** One-line summary for the status bar. */
 export function serversSummary(servers: readonly ServerEntry[]): { text: string; tone: "ok" | "busy" | "error" | "idle" } | null {
   if (!servers.length) return null;
-  const bad = servers.filter((s) => s.status === "crashed" || s.status === "missing" || s.status === "misconfigured");
+  const bad = servers.filter(
+    (s) => s.status === "crashed" || s.status === "misconfigured" || (s.status === "missing" && !servedByOther(s, servers)),
+  );
   const busy = servers.filter((s) => s.status === "starting" || s.status === "busy");
   const tone = bad.length ? "error" : busy.length ? "busy" : servers.some((s) => s.status === "ready") ? "ok" : "idle";
   const names = [...new Set(servers.map((s) => s.name))];

src/features/project-tree/ProjectView.tsx

@@ -28,14 +28,17 @@ import { useEffectiveRoots } from "@/platform/projectRoots";
 import { macStroke, strokeOf } from "@/platform/keymap";
 import { prepareMenuGroups, useFileDecoration } from "@/workbench/contributions";
 import {
+  FILES_DRAG,
   HighlightedText,
   Icon,
   Popup,
+  dragSession,
   Tree,
   acquirePopup,
   fileIconName,
   folderIconName,
   showContextMenu,
+  type DragSession,
   type TreeHandle,
   type TreeRowState,
 } from "@/ui";
@@ -443,6 +446,8 @@ export function ProjectView() {
       startY = e.clientY;
     let active = false;
     let paths: string[] = [];
+    // Files (not folders) can also be dropped on an editor to open them there.
+    let files: DragSession | null = null;
     const move = (ev: PointerEvent) => {
       if (!active) {
         if (Math.hypot(ev.clientX - startX, ev.clientY - startY) < DRAG_THRESHOLD) return;
@@ -454,10 +459,14 @@ export function ProjectView() {
         const nodes = keys.map((k) => m.byKey.get(k)).filter((n): n is ProjectNode => !!n && !n.root && !n.placeholder);
         paths = nodes.map((n) => n.path);
         if (!paths.length) return cleanup();
+        const filePaths = nodes.filter((n) => !n.dir).map((n) => n.path);
+        if (filePaths.length) files = dragSession({ type: FILES_DRAG, payload: filePaths.join("\n") });
       }
       const target = folderAt(containerRef.current, ev.clientX, ev.clientY);
       const valid = target && !paths.some((p) => target.path === p || isInside(target.path, p));
       setDropTarget(valid ? target.key : null);
+      if (target) files?.cancel();
+      else files?.move(ev.clientX, ev.clientY);
       setDrag({
         paths,
         label: paths.length === 1 ? nameOf(paths[0]!) : tx`${paths.length} items`,
@@ -469,8 +478,11 @@ export function ProjectView() {
     const up = (ev: PointerEvent) => {
       const target = active ? folderAt(containerRef.current, ev.clientX, ev.clientY) : null;
       const valid = target && !paths.some((p) => target.path === p || isInside(target.path, p));
+      const session = files;
+      files = null;
       cleanup();
       if (active && valid) void dropPaths(paths, target.path, ev.altKey);
+      else if (active && !target) session?.drop(ev.clientX, ev.clientY);
     };
     const key = (ev: KeyboardEvent) => {
       if (ev.key === "Escape" && active) {
@@ -483,6 +495,7 @@ export function ProjectView() {
       window.removeEventListener("pointermove", move);
       window.removeEventListener("pointerup", up);
       window.removeEventListener("keydown", key, true);
+      files?.cancel();
       setDropTarget(null);
       setDrag(null);
     };

src/features/settings/appearanceRuntime.ts

@@ -8,6 +8,7 @@
 import { executeAction, type Action } from "@/platform/actions";
 import { call, commands, isTauri } from "@/platform/ipc";
 import { useProject } from "@/platform/project";
+import { setDragRequiresAlt } from "@/ui";
 import { ZOOM_LIMITS } from "./model/behaviorSchema";
 import { DEFAULT_SETTINGS, validateSettings, type ValidSettings } from "./model/schema";
 
@@ -126,16 +127,9 @@ export function zoomActions(): Action[] {
 // ---------------------------------------------------------------------------
 // Drag-and-drop with Alt pressed only (tool window buttons and editor tabs)
 
-const DRAG_SOURCES = "[data-stripe-button], [role='tab']";
-
 export function installAltDragGuard(enabled: () => boolean): () => void {
-  const onDragStart = (e: DragEvent) => {
-    if (!enabled() || e.altKey) return;
-    const el = e.target instanceof Element ? e.target : null;
-    if (el?.closest(DRAG_SOURCES)) e.preventDefault();
-  };
-  document.addEventListener("dragstart", onDragStart, true);
-  return () => document.removeEventListener("dragstart", onDragStart, true);
+  setDragRequiresAlt(enabled);
+  return () => setDragRequiresAlt(() => false);
 }
 
 // ---------------------------------------------------------------------------

src/features/vcs/CommitView.tsx

@@ -1,6 +1,6 @@
 /** Commit tool window: change list with inclusion checkboxes, message, stashes. */
 import { useWorkflowSettings } from "@/platform/workflowSettings";
-import { useCallback, useEffect, useMemo, useRef, useState, type DragEvent, type MouseEvent } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState, type MouseEvent, type PointerEvent } from "react";
 import { tx } from "@/platform/i18n";
 import clsx from "clsx";
 import { executeAction } from "@/platform/actions";
@@ -18,7 +18,9 @@ import {
   Tabs,
   Tree,
   fileIconName,
+  registerDropTarget,
   showContextMenu,
+  startPointerDrag,
   type MenuItem,
   type TreeHandle,
   T,
@@ -424,35 +426,38 @@ function ChangesPanel() {
                     {n.label}
                   </span>
                 );
+                // Pointer-driven (HTML5 drag and drop never reaches the Tauri webview):
+                // files and folders drag; any row takes them into its changelist.
+                const list = n.changelist;
                 const dnd =
-                  n.changelist !== undefined
-                    ? {
-                        draggable: n.type !== "group",
-                        onDragStart: (e: DragEvent<HTMLSpanElement>) => {
-                          const paths =
-                            selected.has(n.key) && selected.size > 1
-                              ? filesOf(selectedNodes()).map((f) => f.path)
-                              : n.files.map((f) => f.path);
-                          e.dataTransfer.setData(CHANGES_MIME, paths.map(stripSlash).join("\n"));
-                          e.dataTransfer.effectAllowed = "move";
-                        },
-                        onDragOver: (e: DragEvent<HTMLSpanElement>) => {
-                          if (![...e.dataTransfer.types].includes(CHANGES_MIME)) return;
-                          e.preventDefault();
-                          e.dataTransfer.dropEffect = "move";
-                          if (dropTarget !== n.changelist) setDropTarget(n.changelist ?? null);
-                        },
-                        onDragLeave: () => setDropTarget(null),
-                        onDrop: (e: DragEvent<HTMLSpanElement>) => {
-                          const data = e.dataTransfer.getData(CHANGES_MIME);
-                          setDropTarget(null);
-                          if (!data || !n.changelist) return;
-                          e.preventDefault();
-                          moveToChangelist(data.split("\n"), n.changelist);
-                        },
-                        onDragEnd: () => setDropTarget(null),
-                      }
-                    : {};
+                  list === undefined
+                    ? {}
+                    : {
+                        ref: (el: HTMLSpanElement | null) =>
+                          el
+                            ? registerDropTarget(el, {
+                                accepts: (type) => type === CHANGES_MIME,
+                                over: () => setDropTarget(list),
+                                leave: () => setDropTarget(null),
+                                drop: (data) => {
+                                  setDropTarget(null);
+                                  moveToChangelist(data.payload.split("\n"), list);
+                                },
+                              })
+                            : undefined,
+                        ...(n.type !== "group" && {
+                          onPointerDown: (e: PointerEvent<HTMLSpanElement>) => {
+                            const paths =
+                              selected.has(n.key) && selected.size > 1
+                                ? filesOf(selectedNodes()).map((f) => f.path)
+                                : n.files.map((f) => f.path);
+                            startPointerDrag(e, e.currentTarget, {
+                              type: CHANGES_MIME,
+                              payload: paths.map(stripSlash).join("\n"),
+                            });
+                          },
+                        }),
+                      };
                 return (
                   <span
                     className={clsx(