feat(run): wire Workspace to TerminalView, delete the stream-json Run feature

Combines three tasks that couldn't land as separate commits: the
pre-commit hook's full test run crashes on any intermediate state
where Workspace.tsx still imports the files being deleted, so the
deletion (old RunConsole/useRunStream/run-spawner/stream-json-parser),
the RunSetup/RunHistory type adjustments, and this file's own
TerminalView wiring had to be staged together and committed as one
hook-passable unit.

- Delete RunConsole.tsx, useRunStream.ts, server/lib/run-spawner.js,
  server/lib/stream-json-parser.js and their tests (Task 8).
- Adjust RunSetup.tsx/RunHistory.tsx to the tmux-backed RunHandle/
  RunStartArgs/DashboardRunHistoryItem shapes, remove mode selection
  UI (Task 9).
- Swap Workspace.tsx's chat-bubble run console for TerminalView
  (xterm.js over /ws-pty/:runId), drop the stream-json envelope
  plumbing, update Start/Resume to the new RunStartArgs payload.
  Create onStartFromSetup handler to work with RunSetup's new callback
  shape. Remove mode state and related plumbing. Remove send/followUp
  state (no longer using old RunConsole chat interface).
- Add promptPlaceholderTerminal i18n key to support RunSetup's new
  placeholder text (Task 10).
- Update Workspace.test.tsx to mock TerminalView component.
- Regenerate screens.snapshot.test.tsx snapshot (only Workspace run
  panel changes: terminal container instead of chat bubbles).

client/src/pages/__tests__/Workspace.test.tsx

@@ -237,6 +237,12 @@ vi.mock("../../lib/eventBus", () => ({
   },
 }));
 
+vi.mock("../../components/run/TerminalView", () => ({
+  TerminalView: ({ runId }: { runId: string }) => (
+    <div data-testid="terminal-view" data-run-id={runId} />
+  ),
+}));
+
 import { Workspace } from "../Workspace";
 import { api } from "../../lib/api";