feat(chat): terminal chat parity for every tool; Desktop-like artifacts

- The chat over a terminal pane now covers Claude, Codex, omp, Cursor and
  Antigravity: Cursor's agent transcript and agy's step log
  (brain/<id>/.system_generated/logs/transcript_full.jsonl) are read as
  conversations; Cursor sessions are claimed by their workspace
- Replies appear as soon as they are written: the projects-tree watcher
  broadcasts `transcript_changed` (at most every 250 ms per session) and the
  chat re-reads the transcript while the terminal underneath draws
- Stop shows from the pane's own busy line (Claude/Codex `esc to interrupt`,
  agy `… esc to cancel`), or fresh output for omp/Cursor — no hooks needed
- Permission prompts read off the terminal become a card with the tool, its
  command and "Deny with a note"; Codex gets Permission mode / Model buttons
  that open its own numbered pickers, answered from the menu card
- Artifacts: cards for pages/documents/diagrams/tables/React components, a
  Preview | Code panel with versions, copy, download, save to the Artifacts
  Hub, full screen; sandboxed iframes without allow-same-origin
- Claude panes get CLAUDE_CODE_ENABLE_TODO_TOOLS=1 so the Progress panel has a
  plan; multi-question pane menus read their Next row and question tabs
- The realtime chat bridge (structured stdio, /api/chat-bridge, /ws-chat)
  from the unreleased ad9d475 is not kept

client/src/components/run/PaneGrid.tsx

@@ -70,7 +70,7 @@ import {
 } from "../../lib/paneLayout";
 import { AiToolIcon } from "../AiToolIcon";
 import { RunDot, type RunState } from "./ConsoleTabs";
-import { setSessionChat, useSessionChat } from "../../lib/chatUi";
+import { CHAT_TOOLS, setSessionChat, useSessionChat } from "../../lib/chatUi";
 import { readChatDraft, writeChatDraft } from "../../lib/chatDraft";
 import { pasteToRun, takeRunInput } from "../../lib/panePaste";
 import { promptForPane } from "./RunSetup";
@@ -238,7 +238,7 @@ function PaneMenu({
 const ITEM =
   "flex w-full items-center gap-2.5 rounded-md px-2.5 py-1.5 text-left text-sm text-fg-secondary hover:bg-surface-4 hover:text-fg-primary";
 
-/** Chat UI ⇄ terminal for a Claude/Codex pane — this session's own view
+/** Chat UI ⇄ terminal for a `CHAT_TOOLS` pane — this session's own view
  *  (`lib/chatUi.ts`); a session with no id yet has no chat to show. The
  *  unsent prompt goes along: the terminal's input box into the chat's draft,
  *  the draft (its files as paths) back into the input box, never sent. */
@@ -254,7 +254,7 @@ export function showTerminal(runId: string, sessionId: string, tool?: string) {
 function ChatToggle({ run }: { run?: RunHandle }) {
   const { t } = useTranslation("lanes");
   const chat = useSessionChat(run?.sessionId);
-  if (!run?.sessionId || (run.tool !== "claude" && run.tool !== "codex")) return null;
+  if (!run?.sessionId || !CHAT_TOOLS.has(run.tool)) return null;
   const sessionId = run.sessionId;
   const label = chat ? t("panes.showTerminal") : t("panes.showChat");
   return (