fix(tmux): isolate sessions on a dedicated socket + raise pane nofile limit (fixes new-session crash after tmux upgrade) (#96)

* fix: isolate codeman tmux sessions

* fix(tmux): unify all sessions onto a single dedicated socket

Remove the per-session `tmuxSocket` field that recorded which tmux server
each session lived on (default vs the `codeman` socket). That field was a
persisted cache of physical reality and could drift — causing live sessions
to be wrongly marked dead ("tab shows no session found") and spawning
duplicate "Restored:" tabs.

All Codeman sessions now live on one process-wide socket (`tmux -L codeman`,
overridable via CODEMAN_TMUX_SOCKET), exposed via TmuxManager.muxSocket on
the TerminalMultiplexer interface. reconcileSessions() collapses from a
multi-socket scan (locate / re-pin / cross-socket dedup) to a single
`list-panes` query. loadSessions() strips the obsolete field from on-disk
records so it stops being written back.

Also fix two sibling bare-`tmux` call sites the unification would otherwise
leave broken (same #80 regression class — bare tmux hits the user's default
server and never finds a session on the codeman socket):
- session.ts queryTmuxWindowSize(): add `-L <socket>` (was silently falling
  back to 120x40 on re-attach, losing scrollback)
- session-routes.ts send-key (Shift+Enter / Ctrl+Enter newline): route
  through ctx.mux.muxSocket

SSH chooser scripts (tmux-manager.sh, tmux-chooser.sh) route every tmux call
through `tmux -L $CODEMAN_TMUX_SOCKET`, matching the TS default.

---------

Co-authored-by: Teigen <teigen@TeigendeMac-mini.local>

src/session.ts

@@ -133,15 +133,22 @@ const TMUX_DISPLAY_TIMEOUT_MS = 2000;
  * (tmux dead, muxName unknown, malformed output) — caller never has to
  * differentiate "tmux unreachable" from "size 120x40".
  *
+ * `socket` MUST be the same dedicated socket the session lives on (`mux.muxSocket`);
+ * querying the default server would never find the session and silently fall back.
+ *
  * Argv form (execFileSync, not execSync) keeps `muxName` out of any shell so
  * a hostile session name can't inject options.
  */
-export function queryTmuxWindowSize(muxName: string): { cols: number; rows: number } {
+export function queryTmuxWindowSize(muxName: string, socket: string): { cols: number; rows: number } {
   try {
-    const sizeStr = execFileSync('tmux', ['display', '-t', muxName, '-p', '#{window_width} #{window_height}'], {
-      timeout: TMUX_DISPLAY_TIMEOUT_MS,
-      encoding: 'utf8',
-    }).trim();
+    const sizeStr = execFileSync(
+      'tmux',
+      ['-L', socket, 'display', '-t', muxName, '-p', '#{window_width} #{window_height}'],
+      {
+        timeout: TMUX_DISPLAY_TIMEOUT_MS,
+        encoding: 'utf8',
+      }
+    ).trim();
     const [w, h] = sizeStr.split(' ').map(Number);
     if (w > 0 && h > 0) {
       return { cols: w, rows: h };
@@ -978,7 +985,7 @@ export class Session extends EventEmitter {
 
     // Attach to the mux session via PTY
     // Query existing tmux window size so re-attach matches (avoids flicker from 120x40 default)
-    const { cols: ptyCols, rows: ptyRows } = queryTmuxWindowSize(this._muxSession!.muxName);
+    const { cols: ptyCols, rows: ptyRows } = queryTmuxWindowSize(this._muxSession!.muxName, mux.muxSocket);
     try {
       this.ptyProcess = pty.spawn(mux.getAttachCommand(), mux.getAttachArgs(this._muxSession!.muxName), {
         name: 'xterm-256color',