feat: Align editor, workbench, run/debug and VCS interactions with IntelliJ IDEA

Keymap
- Let AltGr characters through instead of firing Ctrl+Alt shortcuts (Windows/Linux)
- Double Shift: strict press/release timing, ignored while typing or after Shift+click
- Chords wait 2s and swallow an unmatched second stroke
- Drop CodeMirror defaults that clash with IDEA keys; ⌘Enter is Split Line, add
  Scroll to Center and Code Block Start/End
- Add missing IDEA defaults (⌃J, ⌘Y, ⇧⌘C, ⌥⌘Y, ⇧⌘M, F9 Resume, ⌘R Rerun, …)

Editor
- Tab inserts at the caret; smart Backspace to the proper indent; Enter continues
  a `//` comment; per-language line comment placement
- Back/Forward records navigations only; ⌘F searches the selected text
- In-place rename; ⌃Space inserts a sole candidate; commit characters only for a
  focused lookup; usage highlighting survives edits; ⌥Enter offers fixes from the
  caret line; ⌘-hover shows declaration info only for navigable targets

Workbench
- Tool windows: primary and split area per side, six Move To anchors, layout migration
- ⌘W closes tool window content; Shift+Esc from the editor; closing a tab
  activates the left neighbour; preview tab and tab limit follow IDEA defaults
- Switcher lists open editors and tool windows; Recent Files Delete removes items
- Search Everywhere tab/scope behaviour; popups close when the window deactivates
- Project view: Copy/Move dialogs on paste, skippable usage search on delete,
  new-file input cancels on blur; Settings search Esc clears the filter
- Status bar breadcrumbs open a children popup; notification timeouts

Run / Debug / Build / Terminal
- Run asks to stop a running single-instance config; Rerun restarts silently;
  "Allow multiple instances" option
- Run chooser: Enter runs, Shift debugs, F4/Delete/digits
- Type into the console for stdin; Stop covers debug sessions
- Log (Shift+click) and temporary (Alt+click) breakpoints; independent suspend/log
  options; Evaluate prefill and history; changed-value highlighting; expandable hints
- Build window opens on failure and jumps to the first error
- Terminal confirms closing a busy tab and lets IDE shortcuts through

VCS
- Correct ours/theirs labels during rebase, cherry-pick and revert
- Smart/Force Checkout; remote branch checkout updates the local branch
- Partial commit by changed block; inline before-commit check results
- F7 continues into the next file; Rollback Lines; Commit and Push; Amend message swap
- Branch delete with Restore; force push confirmation; editable push target;
  update summary with the incoming commits

src/features/debugger/editor/editor.module.css

@@ -134,7 +134,6 @@
   user-select: none;
 }
 
-
 /* Data Views › Show value tooltip on mouse hover. */
 .valueTooltip {
   max-width: 520px;
@@ -144,6 +143,29 @@
   white-space: pre-wrap;
   word-break: break-word;
 }
+.valueTooltipTree {
+  padding: 2px 0;
+  white-space: normal;
+}
+.valueExpand {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 16px;
+  height: 16px;
+  margin-right: 4px;
+  padding: 0;
+  border: 0;
+  border-radius: var(--radius-small);
+  background: transparent;
+  color: var(--fg-muted);
+  vertical-align: -3px;
+  cursor: pointer;
+}
+.valueExpand:hover {
+  background: var(--bg-hover, transparent);
+  color: var(--fg-strong);
+}
 .valueName {
   color: var(--fg-strong);
 }