fix: hardening round from code review (4 P1 + 15 P2)

P1:
- settingsStore: back up an unparseable settings.json to .bak before
  falling back to defaults, so the next mutation can no longer silently
  wipe custom themes/highlight rules
- ptyDispatcher: fan out per-session data/exit handlers (Set instead of
  a single slot) so SSH split panes stop stealing each other's stream
- FilePanel: monotonic refresh token keeps stale listings from painting
  over a newer navigation; upload finish no longer yanks the panel back
- settings.css: active settings-tab label derives from --chrome-fg so it
  stays visible on the shipped light themes

P2 (main/renderer):
- paste guard: a paste ending in a newline always confirms
- Workspace: closing an SSH pane no longer seeds the local cwd with a
  remote path
- tray: skip close-dialog continuation on a destroyed window
- commands: close zombie 'in-progress' session logs at hydrate
- zmodem: clear the stale offer timer before arming a new one
- connectionsStore: coerce/validate renderer input before persisting
- sftp: OperationError marker class keeps translated errors out of the
  transport-retry classifier
- CommandsPanel: surface save failures inside the dialog
- ConnectionSidebar: drop a tautological tooltip condition

P2 (i18n/tooling/tests):
- localize the 16 ANSI color labels and the highlight sample text
  (21 new keys across zh-CN/zh-TW/en/ja)
- sync-changelog: keep ### subheadings, normalize CRLF notes
- release.cjs: GitHub release reuse-by-tag (idempotent re-runs); fail
  loudly on a failed Gitea asset listing
- commands-store test: absent historyEnabled now truly tests absence

scripts/sync-changelog.cjs

@@ -33,10 +33,15 @@ const sync = ({ notes, changelog, header, required }) => {
 
   const body = fs
     .readFileSync(notesPath, 'utf8')
-    // Drop the notes' own title / `## vX` heading: the section heading is built
-    // here so every changelog stays uniform (`## vX.Y.Z - date`).
-    .replace(/^#.*\n/gm, '')
-    .replace(new RegExp(`^## v${pkgVersion}.*\\n`), '')
+    // Normalize newlines first: a CRLF notes file would otherwise keep its `\r`
+    // in every line, and the join below re-adds the changelog's ending on top —
+    // every line of the merged section rendering as `\r\r\n` (doubled blanks).
+    .replace(/\r\n/g, '\n')
+    // Drop only the notes' own title and the `## v<pkgVersion>` heading: the
+    // section heading is built here so every changelog stays uniform
+    // (`## vX.Y.Z - date`). Stripping every `#`-line (the old behaviour) also
+    // removed `###` subheadings, merging 新功能/修复 groups into one flat list.
+    .replace(new RegExp(`^# .*\\n|^## v${pkgVersion}.*\\n`, 'gm'), '')
     .replace(/^\s+/, '')
     .trimEnd()