fix: list and open sessions across project directories

Sessions outside the server's launch directory were invisible and returned
404 on open, leaving the model picker empty. List without the SDK's
process-cwd filter and normalize working directories at the API boundary and
when reading stored session data, tolerating separator/normalization
differences (including Windows backslash vs forward slash). Requires Pi
coding agent SDK 0.78.0 or newer.

src/server/sessions/piSessionManagerGateway.ts

@@ -3,6 +3,7 @@ import { readdir } from "node:fs/promises";
 import { homedir } from "node:os";
 import { dirname, isAbsolute, join, resolve } from "node:path";
 import { getAgentDir, SessionManager, SettingsManager } from "@earendil-works/pi-coding-agent";
+import { canonicalizeStoredCwd, cwdPathsEqual } from "../workingDirectory.js";
 import type { PiSessionListEntry, PiSessionManager, PiSessionManagerGateway } from "./piSessionService.js";
 
 export const PI_SESSION_DIR_ENV = "PI_CODING_AGENT_SESSION_DIR";
@@ -77,7 +78,13 @@ class SettingsAwarePiSessionManagerGateway implements PiSessionManagerGateway {
 }
 
 export async function listSessionsInDir(sessionDir: string): Promise<PiSessionListEntry[]> {
-  return SessionManager.list("", sessionDir);
+  // listAll(sessionDir) lists without the SDK's internal cwd filter, which would
+  // otherwise compare against this process's cwd and drop other projects' sessions.
+  // Cwd filtering is applied explicitly by filterSessionsForCwd where needed.
+  // Session file headers are written by external tools (Pi CLI, SDK consumers),
+  // so their cwd is canonicalized here before it enters pi-web.
+  const sessions = await SessionManager.listAll(sessionDir);
+  return sessions.map((session) => ({ ...session, cwd: canonicalizeStoredCwd(session.cwd) }));
 }
 
 export async function listSessionsInDefaultPiStore(storeRoot = defaultPiSessionsRoot()): Promise<PiSessionListEntry[]> {
@@ -94,7 +101,9 @@ export async function listSessionsInDefaultPiStore(storeRoot = defaultPiSessions
 }
 
 export function filterSessionsForCwd(sessions: readonly PiSessionListEntry[], cwd: string): PiSessionListEntry[] {
-  return sessions.filter((session) => session.cwd === cwd);
+  // Sessions with an empty cwd (old session files) are excluded: resolve("") would
+  // resolve to this process's cwd and produce false matches.
+  return sessions.filter((session) => session.cwd !== "" && cwdPathsEqual(session.cwd, cwd));
 }
 
 export function defaultPiSessionsRoot(agentDir = getAgentDir()): string {