refactor: remove terminal agent concept entirely

Remove the "agent can be a terminal" branching from the entire codebase.
An agent is now always a session-backed chat agent. Standalone terminal
infrastructure (terminal component, ANSI handling, terminal-stream-protocol)
is preserved.

Server: delete ManagedTerminalAgent, AgentKind, TerminalExitDetails,
launchTerminalAgent, registerTerminalAgent, handleTerminalAgentExited,
supportsTerminalMode capability, buildTerminalCreate/ResumeCommand from
all providers, terminal agent persistence/projections.

App: delete terminal-agent-panel.tsx, terminal-agent-reopen-store.ts,
terminal/terminalExit fields on agent state, "Terminal Agents" launcher
section, terminal-agent workspace setup flow, terminal badge in agent list.

CLI: remove terminal column from ls, terminal-agent error from send.

60 files changed, -3592 lines

packages/app/e2e/helpers/launcher.ts

@@ -89,12 +89,6 @@ export async function waitForLauncherPanel(page: Page): Promise<void> {
   });
 }
 
-/** Assert that the launcher panel shows provider tiles under "Terminal Agents". */
-export async function assertProviderTilesVisible(page: Page): Promise<void> {
-  await expect(page.getByText("Terminal Agents", { exact: true }).first()).toBeVisible({
-    timeout: 10_000,
-  });
-}
 
 /** Assert the launcher panel has a "New Chat" tile. */
 export async function assertNewChatTileVisible(page: Page): Promise<void> {
@@ -122,12 +116,6 @@ export async function clickTerminal(page: Page): Promise<void> {
   await button.click();
 }
 
-/** Click a provider tile by label (e.g. "Claude Code", "Codex"). */
-export async function clickProviderTile(page: Page, providerLabel: string): Promise<void> {
-  const tile = page.getByRole("button", { name: providerLabel }).first();
-  await expect(tile).toBeVisible({ timeout: 10_000 });
-  await tile.click();
-}
 
 // ─── Tab title assertions ──────────────────────────────────────────────────
 

packages/app/e2e/helpers/workspace-lifecycle.ts

@@ -1,11 +1,9 @@
 import { expect, type Page } from "@playwright/test";
 import {
   clickNewChat,
-  clickProviderTile,
   clickTerminal,
   countTabsOfKind,
   getTabTestIds,
-  waitForTabWithTitle,
 } from "./launcher";
 import { setupDeterministicPrompt, waitForTerminalContent } from "./terminal-perf";
 
@@ -35,13 +33,6 @@ export async function createStandaloneTerminalFromLauncher(page: Page): Promise<
   await expect.poll(async () => (await getTabTestIds(page)).length).toBe(tabIdsBefore.length);
 }
 
-export async function createTerminalAgentFromLauncher(page: Page, providerLabel: string): Promise<void> {
-  await clickProviderTile(page, providerLabel);
-  await expect(page.getByTestId("terminal-agent-loading")).toHaveCount(0, { timeout: 30_000 });
-  await expect(terminalSurface(page)).toBeVisible({ timeout: 30_000 });
-  await waitForTabWithTitle(page, /new agent/i);
-}
-
 export async function createAgentChatFromLauncher(page: Page): Promise<void> {
   await clickNewChat(page);
   await expect(composerInput(page)).toBeVisible({ timeout: 15_000 });

packages/app/e2e/helpers/workspace-setup.ts

@@ -186,26 +186,6 @@ export async function createChatAgentFromWorkspaceSetup(
   await dialog.getByRole("button", { name: "Send message" }).click();
 }
 
-export async function createTerminalAgentFromWorkspaceSetup(
-  page: Page,
-  input: { providerLabel: string; prompt?: string },
-): Promise<void> {
-  const dialog = workspaceSetupDialog(page);
-  await dialog.getByRole("button", { name: /Terminal Agent/i }).click();
-
-  const providerButton = dialog.getByRole("button", { name: new RegExp(`^${input.providerLabel}$`, "i") }).first();
-  await expect(providerButton).toBeVisible({ timeout: 15_000 });
-  await providerButton.click();
-
-  if (input.prompt) {
-    const promptInput = dialog.getByPlaceholder("Optional").first();
-    await expect(promptInput).toBeVisible({ timeout: 15_000 });
-    await promptInput.fill(input.prompt);
-  }
-
-  await dialog.getByRole("button", { name: "Launch" }).click();
-}
-
 export async function createStandaloneTerminalFromWorkspaceSetup(page: Page): Promise<void> {
   await workspaceSetupDialog(page)
     .getByRole("button", { name: /^Terminal Create the workspace/i })