fix(i18n): Translate the remaining UI text (Git, hierarchy, pull requests, dialogs, aria labels) (#114)

Hard-coded UI text, titles and aria-labels in about 110 components (Git panels, hierarchy, pull requests, dialogs, settings, welcome) now go through tx; spliced fragments became whole sentences (fileCount, noneFoundLabel, hierarchyTitle) and pull request states use keyed messages. 225 zh entries added, stale fragment entries removed.

Also: tx used as a tag without interpolations (tx`No checks`) now looks the text up exactly instead of as a template, so it is translated like tx("No checks"); the text-catalog test checks such tags as plain literals. Check and test counts reuse the existing "{count} passed" / "{failed} failing" entries.

Claude-Session: https://claude.ai/code/session_01VUYsdXA2nkF5v6zsC93dpn
Co-authored-by: jaw52 <[email protected]>

src/features/github/github.test.ts

@@ -44,7 +44,7 @@ describe("pull request model", () => {
     const c = (status: PrCheck["status"]): PrCheck => ({ name: status, workflow: null, status, url: null });
     const s = checksSummary([c("failure"), c("success"), c("success"), c("pending"), c("skipped")]);
     expect(s).toEqual({ failed: 1, pending: 1, passed: 2, other: 1 });
-    expect(checksText(s)).toBe("1 failing, 1 pending, 2 successful, 1 skipped");
+    expect(checksText(s)).toBe("1 failing, 1 pending, 2 passed, 1 skipped");
     expect(checksText(checksSummary([]))).toBe("No checks");
   });