feat(desktop): session hygiene, archive, media streaming + connecting overlay (#37099)

* feat(desktop): session hygiene, archive, media streaming + connecting overlay

Address a batch of desktop feedback:

- Stop leaking empty "Untitled" sessions: the TUI gateway pre-created a DB
  row on every session.create (i.e. every launch/draft). Persist the row
  lazily on first prompt instead, and hide message-less rows in the sidebar.
- Archive/hide sessions: new `archived` column + set_session_archived, web
  API (`?archived=` + PATCH archived), Ctrl/⌘-click and a context-menu item
  in the sidebar, and an "Archived Chats" settings panel to restore/delete.
- Videos load via a streaming `hermes-media://` protocol instead of capped,
  in-memory data URLs (16 MB limit) — bypasses the cap and supports seeking.
- Background-process completions route to the session that launched them:
  the completion event now carries session_key and each poller only consumes
  its own.
- Sidebar: "Group by workspace" toggle is always visible; each workspace
  group gets a "+" to start a session in that directory; "New agent"/"Agents"
  relabeled to "New session"/"Sessions".
- New gateway connecting overlay (ascii decode → fade out) replacing the bare
  skeleton/"starting gateway" state.

* fix(desktop): bail connecting overlay on boot error

The shownRef latch kept the connecting overlay mounted behind
BootFailureOverlay after a hard boot failure. Return null on boot.error
so the failure recovery surface fully owns the screen.

* fix(desktop): address Copilot review

- /api/sessions: validate `archived` (400 on unknown) and return `archived`
  as a JSON boolean instead of SQLite's 0/1.
- PATCH /api/sessions/{id}: 400 (not a misleading 404) when the body has no
  updatable fields; stop conflating a no-op with "not found".
- hermes-media protocol: drop `bypassCSP` — streaming only needs
  secure/standard/stream/supportFetchAPI.
- Sidebar workspace header: split the toggle and the "+" into sibling buttons
  so we no longer nest interactive elements inside a <button>.

* fix(desktop): address Copilot re-review

- hermes-media protocol: restrict streaming to an audio/video extension
  allowlist (415 otherwise) so it can't be used to read arbitrary local files.
- Connecting overlay: use z-[1200] instead of the non-standard z-1200 utility.

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

apps/desktop/src/hermes.ts

@@ -111,9 +111,13 @@ export class HermesGateway extends JsonRpcGatewayClient {
   }
 }
 
-export async function listSessions(limit = 40, minMessages = 0): Promise<PaginatedSessions> {
+export async function listSessions(
+  limit = 40,
+  minMessages = 0,
+  archived: 'exclude' | 'include' | 'only' = 'exclude'
+): Promise<PaginatedSessions> {
   const result = await window.hermesDesktop.api<PaginatedSessions>({
-    path: `/api/sessions?limit=${limit}&offset=0&min_messages=${Math.max(0, minMessages)}`
+    path: `/api/sessions?limit=${limit}&offset=0&min_messages=${Math.max(0, minMessages)}&archived=${archived}`
   })
 
   return {
@@ -123,6 +127,14 @@ export async function listSessions(limit = 40, minMessages = 0): Promise<Paginat
   }
 }
 
+export function setSessionArchived(id: string, archived: boolean): Promise<{ ok: boolean }> {
+  return window.hermesDesktop.api<{ ok: boolean }>({
+    path: `/api/sessions/${encodeURIComponent(id)}`,
+    method: 'PATCH',
+    body: { archived }
+  })
+}
+
 export function searchSessions(query: string): Promise<SessionSearchResponse> {
   return window.hermesDesktop.api<SessionSearchResponse>({
     path: `/api/sessions/search?q=${encodeURIComponent(query)}`