Keep agent browser tabs connected across workspace switches (#2156)

* fix(desktop): keep browser tabs connected across workspaces

Electron can replace a guest WebContents when a retained browser tab is reparented. Re-register each attachment and keep background actionability checks running so agent browser tools retain the tab through workspace eviction.\n\nCover the full app, daemon, Electron, and MCP path in the existing desktop CI job.

* fix(desktop): launch Electron E2E reliably on Linux

CI Electron must receive --no-sandbox before the app starts because the hosted runner cannot use Electron's bundled SUID sandbox helper. Forward explicit dev-runner arguments and fail readiness waits as soon as a child exits.

* fix(desktop): preserve active browser on repeated registration

* fix(desktop): keep browser keyboard attachment idempotent

* fix(desktop): wait for E2E bridge readiness

* fix(desktop): close E2E logs after output drains

docs/testing.md

@@ -124,6 +124,16 @@ PASEO_DESKTOP_SMOKE_ARTIFACT_DIR=/tmp/paseo-desktop-smoke \
 npm run build:desktop -- --publish never --linux --x64 --dir
 ```
 
+### Browser tab bridge regression
+
+The desktop browser tab bridge E2E launches an isolated real daemon, Metro, and Electron app. It forces workspace LRU eviction to reparent the original tab and replace its guest `WebContents`, then makes one MCP call each for tab listing, snapshot, and click against that original browser id. A final MCP wait proves the real target page received the click.
+
+Run it locally with the same command owned by the Ubuntu leg of the existing `desktop-tests` CI check:
+
+```bash
+npm run test:e2e:browser-tab-bridge --workspace=@getpaseo/desktop
+```
+
 ## Test organization
 
 - Collocate tests with implementation: `thing.ts` + `thing.test.ts`