feat(lanes): add pipeline-template picker to the Workspace lane header

Lets a lane's pipeline template be switched live from the dashboard
(the same PATCH /api/lanes/:id the CLI's `ccam lanes pipeline` uses),
so lanes created before the picker shipped don't need the terminal.
Both ship-feature skills now force their own template before their
first `ccam stage` call, so the human never has to pick correctly at
lane creation.

client/src/i18n/locales/en/lanes.json

@@ -94,6 +94,8 @@
   "locks.held_one": "{{count}} lock held",
   "locks.held_other": "{{count}} locks held",
   "moreActions": "More actions",
+  "pipelinePicker.label": "Pipeline template",
+  "pipelinePicker.stageMismatch": "Stage \"{{stage}}\" matches no node in \"{{pipeline}}\" — declare one of: {{nodes}}",
   "preflightError": "Could not load the current lane facts.",
   "preflightErrorWithMessage": "Could not load the current lane facts: {{message}}",
   "runtime.boot": "▶ up",