feat(chats): relocate managed chat worktrees via OPENCHAMBER_CHATS_DIR (#3135)

* feat(chats): relocate managed chat worktrees via OPENCHAMBER_CHATS_DIR

Projectless-chat worktrees were hard-pinned to
<home>/.config/openchamber/chats: the UI joined the path client-side,
workspace checks allowed only the config root, and identification matched
the literal path segment. When the OpenCode server runs as a separate
user (UID-separated setups), that root is unreachable — every chat
session answered HTTP 500 (EACCES on the session directory).

The server now owns the chats root. OPENCHAMBER_CHATS_DIR relocates it
(default unchanged: <config root>/chats); /api/fs/home answers
{ home, chatsRoot }; fs workspace checks accept the managed chats root
next to the config root; the client resolves the root from the server
(per-runtime cached, warmed at bootstrap so sync classification sees it)
and falls back to the home join for older servers.

Refs #3130

* chore: trim added comments to local precedent

* fix: forward managedChatsRoot through feature-routes-runtime to registerFsRoutes

* fix(chats): await the root warm-up and keep the legacy chats root owned

Review feedback on #3135:

- bootstrapGlobal now awaits warmChatsRootDirectory, so synchronous
  session classification never sees an empty root cache (relocated
  sessions were grouped as project sessions when the session list
  outran /api/fs/home).
- managedProjectRoots keeps the legacy <config root>/chats entry next to
  OPENCHAMBER_CHATS_DIR, so memory ownership of existing chats survives
  relocation.

* fix(chats): distinguish chats-root fetch failure from older servers

* fix(sync): rehydrate managed chat sessions after the chats root warms

* fix(fs): pass managed roots through the symlink and git-dirs path checks after the main merge

* docs: drop changelog edits; changelog is the maintainer's release-time work

* fix(chats): keep legacy chat directories deletable while the root is relocated

* fix(chats): resolve roots before cleanup and initial session loads

* test(chats): type runtime spies against actual SDK contracts

---------

Signed-off-by: Steffen Mächtel <info@steffen-maechtel.de>
Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

packages/ui/src/sync/persist-cache.test.ts

@@ -1,3 +1,5 @@
+import { opencodeClient } from '@/lib/opencode/client';
+import { ensureChatsRootDirectory } from '@/lib/chatDirectories';
 import { afterEach, beforeEach, describe, expect, test } from "bun:test"
 import type { Session } from "@opencode-ai/sdk/v2/client"
 import { switchRuntimeEndpoint } from "@/lib/runtime-switch"
@@ -69,10 +71,14 @@ const session = (
   time: { created: updated - 1, updated },
 } as Session)
 
-beforeEach(() => {
+beforeEach(async () => {
   storage = new TestStorage()
   Object.defineProperty(globalThis, "localStorage", { configurable: true, value: storage })
   switchRuntimeEndpoint({ apiBaseUrl: "https://runtime-default.test", runtimeKey: "runtime-default" })
+  const originalHomeInfo = opencodeClient.getFilesystemHomeInfo
+  opencodeClient.getFilesystemHomeInfo = async () => ({ home: '/home/user' })
+  await ensureChatsRootDirectory()
+  opencodeClient.getFilesystemHomeInfo = originalHomeInfo
 })
 
 afterEach(() => {