fix(mux): give a discovered tmux session its pane's directory, not the server cwd

reconcileSessions() adopts codeman-* sessions it finds on the socket but has
no record of (a lost or stale mux-sessions.json) as "Restored: ..." entries,
and set their workingDir to process.cwd(). Every such session then looked like
it lived wherever the server was started, and a later respawn of it cd'd
there instead of into its project.

tmux already knows the answer as #{pane_current_path}. It is appended as the
last field of PANE_LIST_FORMAT, so a directory containing the separator stays
whole, and parsePaneRows() reads it as PaneRow.currentPath. No extra tmux call:
the same list-panes read that yields the pid now yields the directory.

The path is set by whoever owns the pane, so it is admitted only if it passes
isValidPath(), the check createSession() and respawnPane() already apply to a
workingDir; otherwise, and when tmux reported none, process.cwd() stays the
fallback. A hand-split session takes the first pane tmux lists.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/tmux-manager.ts

@@ -252,10 +252,14 @@ const PANE_LIST_SEP = '|';
  * know a variable substitutes the empty string rather than failing, which is how
  * tmux 3.2a answers `#{pane_dead_signal}` (added in 3.4), and the parser reads a
  * short row as "pid known, deadness unknown" rather than discarding it.
+ *
+ * `#{pane_current_path}` comes last on purpose: a directory name may contain the
+ * separator, and only the final field can absorb it without ambiguity.
  */
 const PANE_LIST_FORMAT =
   `#{session_name}${PANE_LIST_SEP}#{pane_pid}` +
-  `${PANE_LIST_SEP}#{pane_dead}${PANE_LIST_SEP}#{pane_dead_status}${PANE_LIST_SEP}#{pane_dead_signal}`;
+  `${PANE_LIST_SEP}#{pane_dead}${PANE_LIST_SEP}#{pane_dead_status}${PANE_LIST_SEP}#{pane_dead_signal}` +
+  `${PANE_LIST_SEP}#{pane_current_path}`;
 
 /**
  * 构建 pane 启动前的 nofile 修复命令。
@@ -282,6 +286,8 @@ export interface PaneRow {
   exitStatus?: number;
   /** `#{pane_dead_signal}` — the killing signal, absent before tmux 3.4 and when unsignalled. */
   exitSignal?: number;
+  /** `#{pane_current_path}` — the pane's current directory, absent when tmux reported none. */
+  currentPath?: string;
 }
 
 /**
@@ -347,6 +353,8 @@ export function parsePaneRows(output: string): PaneRow[] {
       dead: deadFlag === '1' ? true : deadFlag === '0' ? false : undefined,
       exitStatus: paneField(fields, 3),
       exitSignal: paneField(fields, 4),
+      // Everything after the fifth separator, so a path containing `|` stays whole.
+      currentPath: fields.slice(5).join(PANE_LIST_SEP) || undefined,
     });
   }
   return rows;
@@ -3115,6 +3123,7 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
     // socket tag to reconcile and no cross-socket ambiguity that could mark a
     // live session dead (the root cause of vanished/duplicate tabs).
     let active: Map<string, number>;
+    const paneDirs = new Map<string, string>();
     try {
       const output = execSync(`${this.tmux()} list-panes -a -F '${PANE_LIST_FORMAT}' 2>/dev/null || true`, {
         encoding: 'utf-8',
@@ -3122,6 +3131,14 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
       }).trim();
       const rows = parsePaneRows(output);
       active = new Map(rows.map((row) => [row.sessionName, row.pid]));
+      // A discovered session's directory, from its first pane with a usable path.
+      // The path is admitted only if it passes the same check createSession and
+      // respawnPane apply, since it was set by whoever owns the pane, not by us.
+      for (const row of rows) {
+        if (row.currentPath && !paneDirs.has(row.sessionName) && isValidPath(row.currentPath)) {
+          paneDirs.set(row.sessionName, row.currentPath);
+        }
+      }
       // The same read answers both questions, so recovery starts with a pane-exit
       // reading rather than waiting for the first stats tick — which may never
       // come, since the collector only starts when boot found a live session.
@@ -3175,7 +3192,8 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
         muxName: sessionName,
         pid,
         createdAt: Date.now(),
-        workingDir: process.cwd(),
+        // Where the pane actually works, when tmux said; the server's cwd is only a fallback.
+        workingDir: paneDirs.get(sessionName) ?? process.cwd(),
         mode: 'claude',
         attached: false,
         name: `Restored: ${sessionName}`,