feat(cli): add sessions list/resume/destroy subcommands (#146)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

packages/cli/src/tui/gateway-api.ts

@@ -15,6 +15,21 @@ export interface ProviderInfo {
   models: ModelInfo[];
 }
 
+export interface SessionInfo {
+  id: string;
+  provider: string;
+  modelId: string;
+  createdAt: string;
+  promptCount: number;
+  channels: string[];
+  durationMs: number;
+}
+
+export interface SessionListResult {
+  sessions: SessionInfo[];
+  total: number;
+}
+
 /**
  * Fetch the list of available models from the gateway.
  * Returns an empty array on network or auth errors so the TUI can still function.
@@ -60,3 +75,40 @@ export async function fetchProviders(
     return [];
   }
 }
+
+/**
+ * Fetch the list of active agent sessions from the gateway.
+ * Throws on network or auth errors.
+ */
+export async function fetchSessions(
+  gatewayUrl: string,
+  sessionCookie: string,
+): Promise<SessionListResult> {
+  const res = await fetch(`${gatewayUrl}/api/sessions`, {
+    headers: { Cookie: sessionCookie, Origin: gatewayUrl },
+  });
+  if (!res.ok) {
+    const body = await res.text().catch(() => '');
+    throw new Error(`Failed to list sessions (${res.status}): ${body}`);
+  }
+  return (await res.json()) as SessionListResult;
+}
+
+/**
+ * Destroy (terminate) an agent session on the gateway.
+ * Throws on network or auth errors.
+ */
+export async function deleteSession(
+  gatewayUrl: string,
+  sessionCookie: string,
+  sessionId: string,
+): Promise<void> {
+  const res = await fetch(`${gatewayUrl}/api/sessions/${encodeURIComponent(sessionId)}`, {
+    method: 'DELETE',
+    headers: { Cookie: sessionCookie, Origin: gatewayUrl },
+  });
+  if (!res.ok && res.status !== 204) {
+    const body = await res.text().catch(() => '');
+    throw new Error(`Failed to destroy session (${res.status}): ${body}`);
+  }
+}