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

src/main/sftp.ts

@@ -65,6 +65,14 @@ const sftpCache = new Map<string, SFTPWrapper>()
  */
 class SessionGoneError extends Error {}
 
+/**
+ * Our own "operation failed for a non-transport reason" error (server-side
+ * failure summary, user cancellation). isTransportError rejects these outright:
+ * their messages are translated and can embed remote paths/output, so text
+ * matching would make the retry decision locale- and filename-dependent.
+ */
+class OperationError extends Error {}
+
 async function sftpOf(sessionId: string): Promise<SFTPWrapper> {
   const cached = sftpCache.get(sessionId)
   if (cached) return cached
@@ -100,9 +108,16 @@ function evictSftp(sessionId: string): void {
  * already exists) mean the CHANNEL IS ALIVE — retrying them would just open
  * another subsystem channel, which strict sshd (MaxSessions 2) punishes by
  * dropping the whole connection. Only transport-level death retries.
+ *
+ * Classification is class-based for our own errors (SessionGoneError /
+ * OperationError) and matches only the ssh2 library's own message strings for
+ * the rest: ssh2 is English-only and never translated, so the decision cannot
+ * drift with the UI locale (our translated messages arrive as OperationError
+ * and are rejected before any text is inspected).
  */
 function isTransportError(err: unknown): boolean {
   if (err instanceof SessionGoneError) return true
+  if (err instanceof OperationError) return false
   const msg = (err as Error | undefined)?.message ?? ''
   return /not connected|ECONNRESET|EPIPE|timed out|disconnected|channel|read past end|no response/i.test(msg)
 }
@@ -211,7 +226,7 @@ export function deleteRemote(sessionId: string, paths: string[]): Promise<void>
       }
     }
     if (failures.length > 0) {
-      throw new Error(t('main.sftp.deleteFailed', { detail: failures.join('; ') }))
+      throw new OperationError(t('main.sftp.deleteFailed', { detail: failures.join('; ') }))
     }
   })
 }
@@ -329,7 +344,7 @@ export function uploadRemote(
               let pos = 0
               let lastEmit = 0
               for (;;) {
-                if (transfer.cancelled) throw new Error(t('main.sftp.cancelled'))
+                if (transfer.cancelled) throw new OperationError(t('main.sftp.cancelled'))
                 if (firstError) throw firstError
                 while (inflight.size >= UPLOAD_WINDOW) {
                   await Promise.race(inflight)
@@ -420,7 +435,7 @@ export function downloadRemote(
               let lastEmit = 0
               const buf = Buffer.alloc(CHUNK)
               for (;;) {
-                if (transfer.cancelled) throw new Error(t('main.sftp.cancelled'))
+                if (transfer.cancelled) throw new OperationError(t('main.sftp.cancelled'))
                 const { bytesRead } = await p<{ bytesRead: number; buffer: Buffer }>(cb =>
                   sftp.read(handle, buf, 0, CHUNK, pos, cb)
                 )