Context bar: match panes by live cwd via OSC 7 (was keyed on unset leaf.cwd)

The context indicator never showed because it matched on leaf.cwd, which
is almost always undefined (newLeaf sets none; the shell picker never
supplies one) — so the cwd<->transcript match never hit.

Fix: report each WSL pane's real working directory.
- pty.rs: inject PROMPT_COMMAND (forwarded via WSLENV) so the WSL shell
  emits OSC 7 (file://host/path) on every prompt. Default Ubuntu bash
  inherits an env-provided PROMPT_COMMAND; a shell that hard-assigns it,
  or a non-bash login shell, just won't report (indicator stays hidden,
  no breakage).
- XtermPane: register an OSC 7 handler, decode the path, emit onCwd.
- LeafPane: track liveCwd from onCwd and match the session on
  (liveCwd ?? leaf.cwd). OSC 7 fires at the bash prompt right before
  'claude' launches, so liveCwd is exactly claude's launch cwd; it also
  follows 'cd'.

tsc clean. Rust builds on the Windows host; needs runtime verification.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/XtermPane.tsx

@@ -82,6 +82,10 @@ interface XtermPaneProps {
    *  Defined as an optional callback so single-pane windows don't require
    *  wiring it up. */
   onNavigate?: (intent: NavigateIntent) => void;
+  /** Fired with the shell's reported working directory (from an OSC 7 escape,
+   *  which WSL panes emit via an injected PROMPT_COMMAND — see pty.rs). Used to
+   *  map the pane to the claude session running in it. */
+  onCwd?: (cwd: string) => void;
 }
 
 const DEFAULT_XTERM_FONT_SIZE = 13;
@@ -101,6 +105,7 @@ export default function XtermPane({
   focusTrigger = 0,
   fontSize,
   onNavigate,
+  onCwd,
 }: XtermPaneProps) {
   const containerRef = useRef<HTMLDivElement>(null);
   const termRef = useRef<Terminal | null>(null);
@@ -121,6 +126,7 @@ export default function XtermPane({
   const onDataReceivedRef = useRef(onDataReceived);
   const onFocusRef = useRef(onFocus);
   const onNavigateRef = useRef(onNavigate);
+  const onCwdRef = useRef(onCwd);
   // Stable ref for setSearchOpen so it can be called from inside the
   // attachCustomKeyEventHandler closure without the closure going stale.
   const setSearchOpenRef = useRef<(v: boolean) => void>(setSearchOpen);
@@ -131,6 +137,7 @@ export default function XtermPane({
   useEffect(() => { onDataReceivedRef.current = onDataReceived; }, [onDataReceived]);
   useEffect(() => { onFocusRef.current = onFocus; }, [onFocus]);
   useEffect(() => { onNavigateRef.current = onNavigate; }, [onNavigate]);
+  useEffect(() => { onCwdRef.current = onCwd; }, [onCwd]);
   useEffect(() => { setSearchOpenRef.current = setSearchOpen; }, [setSearchOpen]);
 
   // -------------------------------------------------------------------------
@@ -204,6 +211,24 @@ export default function XtermPane({
     searchAddonRef.current = search;
     term.loadAddon(search);
 
+    // OSC 7 (cwd reporting): WSL panes emit `\e]7;file://<host><path>\e\\` on
+    // every prompt (via the PROMPT_COMMAND we inject at spawn). Capture the
+    // path and report it up so the pane can be matched to its claude session.
+    // Registered before data flows so the first prompt's cwd is caught.
+    term.parser.registerOscHandler(7, (data) => {
+      const m = /^file:\/\/[^/]*(\/.*)$/.exec(data);
+      if (m) {
+        let path = m[1];
+        try {
+          path = decodeURIComponent(path);
+        } catch {
+          /* leave raw if it isn't valid percent-encoding */
+        }
+        onCwdRef.current?.(path);
+      }
+      return true;
+    });
+
     // Initial size — fit before asking the PTY for its dimensions.
     fit.fit();