chat: pwd selector — switch the /chat working directory

The Sessions panel header gets a pwd selector: the default claude_sessions dir,
plus every directory that already has Claude sessions (auto-discovered by reading
the real cwd back from ~/.claude/projects), plus free-text entry. Switching pwd
refetches the list for that cwd's Claude project group and runs New Chat / resume
in it. Backend: GET /chat/pwds + a ?cwd= param on the session ops; the WS handler
honors a chosen cwd for /chat (default claude_sessions). Browse-modal picker next.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/servers/api/chat/claude-sessions.ts

@@ -1,4 +1,4 @@
-import { readdirSync, readFileSync, existsSync, statSync, mkdirSync, rmSync, appendFileSync } from 'node:fs';
+import { readdirSync, readFileSync, existsSync, statSync, mkdirSync, rmSync, appendFileSync, openSync, readSync, closeSync } from 'node:fs';
 import { join } from 'node:path';
 import { DATA_PATH } from '../../data-path';
 
@@ -232,6 +232,66 @@ export function renameClaudeSession(email: string, cwd: string, sessionId: strin
   return true;
 }
 
+// ── Working directories (pwds) ──
+// Every dir you've run Claude in shows up as a project group under ~/.claude/projects. We read the
+// real `cwd` back from each group's transcripts so the UI can offer "jump to any project's sessions".
+
+/** Read the `cwd` recorded in a transcript, from a bounded head read (cwd appears in early entries). */
+function firstCwd(filePath: string): string {
+  let fd: number | undefined;
+  try {
+    fd = openSync(filePath, 'r');
+    const buf = Buffer.alloc(32768);
+    const n = readSync(fd, buf, 0, buf.length, 0);
+    return buf.toString('utf-8', 0, n).match(/"cwd":"([^"]*)"/)?.[1] ?? '';
+  } catch {
+    return '';
+  } finally {
+    if (fd !== undefined) closeSync(fd);
+  }
+}
+
+export type ClaudePwd = { cwd: string; sessionCount: number; updatedAt: string; isDefault: boolean };
+
+/** All working directories that have Claude sessions, plus the default /chat dir. Newest first. */
+export function listClaudePwds(email: string): ClaudePwd[] {
+  const projectsDir = claudeProjectsDir(email);
+  const defaultCwd = getClaudeSessionsCwd(email);
+  const byCwd = new Map<string, { count: number; updatedAt: string }>();
+
+  if (existsSync(projectsDir)) {
+    for (const group of readdirSync(projectsDir)) {
+      const groupDir = join(projectsDir, group);
+      let files: string[];
+      try {
+        files = readdirSync(groupDir).filter((f) => f.endsWith('.jsonl'));
+      } catch {
+        continue; // not a directory
+      }
+      if (files.length === 0) continue;
+
+      const cwd = firstCwd(join(groupDir, files[0]!));
+      if (!cwd) continue;
+      let updatedAt = '';
+      for (const f of files) {
+        const m = statSync(join(groupDir, f)).mtime.toISOString();
+        if (m > updatedAt) updatedAt = m;
+      }
+      const prev = byCwd.get(cwd);
+      byCwd.set(cwd, {
+        count: (prev?.count ?? 0) + files.length,
+        updatedAt: prev && prev.updatedAt > updatedAt ? prev.updatedAt : updatedAt,
+      });
+    }
+  }
+
+  if (!byCwd.has(defaultCwd)) byCwd.set(defaultCwd, { count: 0, updatedAt: '' });
+
+  return [...byCwd.entries()]
+    .map(([cwd, v]) => ({ cwd, sessionCount: v.count, updatedAt: v.updatedAt, isDefault: cwd === defaultCwd }))
+    .sort((a, b) => (a.isDefault ? -1 : b.isDefault ? 1 : b.updatedAt.localeCompare(a.updatedAt)));
+}
+
 /** List sessions Claude has stored for a given working directory, newest first. */
 export function listClaudeSessions(email: string, cwd: string): ClaudeSessionSummary[] {
   const dir = join(claudeProjectsDir(email), projectSlug(cwd));