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/src/screens/workspace/workspace-agent-visibility.test.ts

@@ -19,7 +19,6 @@ function makeAgent(input: {
     serverId: "srv",
     id: input.id,
     provider: "codex",
-    terminal: false,
     status: "idle",
     createdAt,
     updatedAt: createdAt,
@@ -32,7 +31,6 @@ function makeAgent(input: {
       supportsMcpServers: true,
       supportsReasoningStream: true,
       supportsToolInvocations: true,
-      supportsTerminalMode: false,
     },
     currentModeId: null,
     availableModes: [],
@@ -163,9 +161,9 @@ describe("workspace agent visibility", () => {
   it("matches workspace agents using the workspace directory even when the route uses a numeric workspace id", () => {
     const sessionAgents = new Map<string, Agent>([
       [
-        "terminal-agent",
+        "recent-agent",
         makeAgent({
-          id: "terminal-agent",
+          id: "recent-agent",
           cwd: "/tmp/workspace-lifecycle-main",
         }),
       ],
@@ -176,8 +174,8 @@ describe("workspace agent visibility", () => {
       workspaceDirectory: "/tmp/workspace-lifecycle-main",
     });
 
-    expect(result.activeAgentIds).toEqual(new Set(["terminal-agent"]));
-    expect(result.knownAgentIds).toEqual(new Set(["terminal-agent"]));
+    expect(result.activeAgentIds).toEqual(new Set(["recent-agent"]));
+    expect(result.knownAgentIds).toEqual(new Set(["recent-agent"]));
   });
 
   describe("workspaceAgentVisibilityEqual", () => {

packages/app/src/screens/workspace/workspace-draft-agent-tab.tsx

@@ -29,7 +29,6 @@ const DRAFT_CAPABILITIES: AgentCapabilityFlags = {
   supportsMcpServers: false,
   supportsReasoningStream: false,
   supportsToolInvocations: false,
-  supportsTerminalMode: false,
 };
 
 type WorkspaceDraftAgentTabProps = {
@@ -134,7 +133,6 @@ export function WorkspaceDraftAgentTab({
         serverId,
         id: tabId,
         provider: composerState.selectedProvider,
-        terminal: false,
         status: "running",
         createdAt: now,
         updatedAt: now,