test(web): connect a Workspace in the e2e boot path and refresh goldens

The startup-selection flow leaves a fresh world (no Workspace) in the
locked view state, so every e2e scenario that types into the composer
now connects one first via the shared connectFreshWorkspace helper
(hero picker create-by-name dialog; the default 'workspace' name keeps
the session-header cwd assertions intact).

Golden refreshes carry the current composer chrome: the plan/model
control seats are empty until their owning plugins register (the seats
shipped without occupants on this branch), the sidebar shows the
connected workspace group pre-send, and the bash details material
renders Input/code/Output as separate nodes. The cancel scenario polls
the frozen-partial swap instead of counting synchronously — the abort
frame reaches the browser over SSE after the host settles.

apps/web/tests/snapshots/code-mode-round/ui.expected.md

@@ -23,13 +23,7 @@
 - textbox "Message the agent"
 - button "Add attachment":
   - img
-- combobox "Plan mode":
-  - option "Plan" [selected]
-  - option "Agent"
 - combobox "Access mode":
   - option "Read-only" [selected]
   - option "Read-write"
-- combobox "Model":
-  - option "DeepSeek-V4-Pro High" [selected]
-  - option "DeepSeek-V4-Pro"
 - button "Send message" [disabled]