Make workspace IDs opaque, independent of the filesystem path (#1503)

* Make workspace IDs opaque, independent of the filesystem path

Workspace IDs were the resolved checkout/worktree path, so code could
treat an ID as a path: prefix matching, deriving directories from it,
falling back to a path when a lookup missed. IDs are now opaque -
compared only by exact equality and never used as a path. Anything
path-shaped resolves the workspace record first and reads its cwd.

New workspaces get a generated `wks_` ID; existing path-shaped IDs are
read from disk and never regenerated, so there is no migration and no
change to the wire or persisted schemas. Groundwork for running
multiple workspaces in a single directory.

* Keep attachment scope key stable and align refetch test

The attachment scope key keeps `workspace=` instead of `wsid=` so existing
persisted drafts are not orphaned; the rename was cosmetic. The SDK refetch
test no longer asserts a filter, matching refetch fetching one page and
selecting by id client-side.

* Fix live agent updates in directories without a registered workspace

The opaque-ID work removed buildProjectPlacementForCwd's directory
fallback, so an agent running in a folder with no registered workspace
(e.g. a fresh non-git dir) produced a null placement. forwardAgentUpdate
then threw "Workspace not found", the error was swallowed by its catch,
and no agent_update was emitted — live model/thinking switches and status
updates silently stopped. Caught by the live-preferences e2e suite.

The fallback builds a directory-scoped project placement keyed by the
path. That key is a project grouping key (non-git projects group by
path), not a workspace id, so it stays within the opaque-id rule.

* Always run server worktree archive, even without a resolved workspace

Archiving bailed out entirely when the workspace was not found in the
client store, so a race or stale state could make "archive" do nothing
server-side with only a console.warn. The server archive is keyed by
worktreePath, which is always available, so it now runs regardless; only
the optimistic client-side updates (keyed by workspace id) are gated on
the workspace being resolved.

* Expect a directory-scoped placement for unregistered agent dirs

This unit test asserted the no-placement behavior reverted in the live
agent-update fix, which had broken live model/thinking switching. Update
it to expect the directory-scoped placement now emitted for an agent in a
directory with no registered workspace.

* Fix opaque workspace routing in app E2E

* Preserve workspace IDs during partial bootstrap

* Fix archive flows for opaque workspace IDs

* Stop treating opaque workspace IDs as filesystem paths

Workspace IDs are opaque (wks_<hex>), but several call sites still passed
the id where a directory was expected, which broke those flows for opaque
IDs. The branch switcher sent the id as a cwd to branch/stash/checkout git
operations, and server archive/reconcile cleanup keyed git-watch and
subscription teardown by id, leaking that state.

Git and filesystem operations now take the workspace directory; the opaque
id is used only for identity and cache keys. Archive/reconcile cleanup
routes through a single teardownArchivedWorkspace helper that keeps the key
split explicit: runtime store by id, git watch and subscription by cwd.
Path-derived grouping keys are renamed to directory keys, and the helpers
are split into workspace-identity and workspace-directory so the id-vs-path
boundary is obvious.

packages/app/e2e/provider-settings-refresh.spec.ts

@@ -9,7 +9,6 @@ async function openMockAgentAtMobileBreakpoint(page: Page) {
   const session = await seedMockAgentWorkspace({
     repoPrefix: "provider-sheet-stack-",
     title: "Provider sheet stack e2e",
-    initialPrompt: "Prepare provider sheet stack test agent.",
   });
   await openAgentRoute(page, session);
   await expectComposerVisible(page);
@@ -58,6 +57,12 @@ async function closeTopSheet(page: Page) {
   await page.mouse.up();
 }
 
+async function closeSheetByHeaderButton(page: Page, testId: string) {
+  const sheet = page.getByTestId(testId);
+  await sheet.getByLabel("Close", { exact: true }).click({ force: true });
+  await expect(sheet).not.toBeVisible({ timeout: 10_000 });
+}
+
 async function expectProviderSettingsVisible(page: Page) {
   await expect(page.getByTestId("provider-settings-sheet")).toBeVisible({ timeout: 10_000 });
   await expect(page.getByRole("button", { name: "Add model" })).toBeVisible();
@@ -69,14 +74,15 @@ async function exerciseProviderSettingsStack(page: Page) {
 
   await page.getByRole("button", { name: "Add model" }).click();
   await expect(page.getByTestId("add-custom-model-sheet")).toBeVisible({ timeout: 10_000 });
-  await closeTopSheet(page);
+  await closeSheetByHeaderButton(page, "add-custom-model-sheet");
+  await expect(page.getByPlaceholder("e.g. openai/gpt-5")).not.toBeVisible({ timeout: 10_000 });
   await expectProviderSettingsVisible(page);
 
   await page.getByRole("button", { name: "Diagnostic", exact: true }).click();
   await expect(page.getByTestId("provider-diagnostic-sheet")).toBeVisible({ timeout: 10_000 });
   await page.getByRole("button", { name: /Refresh diagnostic/ }).click();
   await expect(page.getByTestId("provider-diagnostic-sheet")).toBeVisible({ timeout: 10_000 });
-  await closeTopSheet(page);
+  await closeSheetByHeaderButton(page, "provider-diagnostic-sheet");
   await expectProviderSettingsVisible(page);
 
   await page.getByRole("button", { name: "Refresh", exact: true }).click();
@@ -87,18 +93,20 @@ test.describe("provider settings bottom-sheet stack", () => {
   test("provider settings and children close back through the model selector stack", async ({
     page,
   }) => {
+    test.setTimeout(180_000);
+
     const session = await openMockAgentAtMobileBreakpoint(page);
 
     try {
       await openProviderSettingsFromModelSelector(page);
       await exerciseProviderSettingsStack(page);
-      await closeTopSheet(page);
+      await closeSheetByHeaderButton(page, "provider-settings-sheet");
 
       await expectModelSelectorVisible(page);
       await page.getByRole("button", { name: /Open .* settings/ }).click();
       await expect(page.getByTestId("provider-settings-sheet")).toBeVisible({ timeout: 10_000 });
       await exerciseProviderSettingsStack(page);
-      await closeTopSheet(page);
+      await closeSheetByHeaderButton(page, "provider-settings-sheet");
 
       await expectModelSelectorVisible(page);
       await closeTopSheet(page);