feat(cli): add mcpctl config prime-agent — proxy MCP + skills sync for prime-agent

Mirror `mcpctl config claude` for prime-agent (which talks to the same mcpctl
proxy MCP gateway over HTTP instead of stdio):

`mcpctl config prime-agent --project X`:
- registers the proxy MCP gateway in ~/.prime/agent/settings.json as
  mcpServers.X = { type: "http", url: <gateway>/projects/X/mcp }, merging with
  any existing servers (e.g. the bundled `sre` project) and preserving all other
  settings
- writes a .mcpctl-project marker so later syncs resolve the project
- syncs the project's skills into ~/.prime/agent/skills/<name>/ as markdown
  skills (prime-agent auto-discovers them at session start)

New `mcpctl skills sync --agent prime-agent` target re-syncs the tree later.

- src/cli/src/config/prime-agent.ts: settings.json read/merge/write helpers
- src/cli/src/utils/prime-agent-skills.ts: prime-agent sync (reuses
  installSkillAtomic + skills-state; skips Claude-only hooks/postInstall)
- completes config.ts/skills.ts wiring; regenerated shell completions
- tests: commands/prime-agent.test.ts + utils/prime-agent-skills.test.ts

src/cli/tests/commands/prime-agent.test.ts

@@ -0,0 +1,147 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { writeFileSync, readFileSync, mkdtempSync, rmSync } from 'node:fs';
+import { join } from 'node:path';
+import { tmpdir } from 'node:os';
+import { createConfigCommand } from '../../src/commands/config.js';
+import type { ApiClient } from '../../src/api-client.js';
+import { DEFAULT_MCPCTL_GATEWAY_URL } from '../../src/config/prime-agent.js';
+
+function mockClient(): ApiClient {
+  return {
+    get: vi.fn(async () => ({})),
+    post: vi.fn(async () => ({ token: 'impersonated-tok', user: { email: 'other@test.com' } })),
+    put: vi.fn(async () => ({})),
+    delete: vi.fn(async () => {}),
+  } as unknown as ApiClient;
+}
+
+describe('config prime-agent', () => {
+  let client: ReturnType<typeof mockClient>;
+  let output: string[];
+  let tmpDir: string;
+  const log = (...args: string[]) => output.push(args.join(' '));
+
+  let prevCwd: string;
+
+  beforeEach(() => {
+    client = mockClient();
+    output = [];
+    tmpDir = mkdtempSync(join(tmpdir(), 'mcpctl-config-prime-agent-'));
+    // config prime-agent writes the .mcpctl-project marker into cwd, so run
+    // every test from an isolated temp dir to avoid polluting the repo.
+    prevCwd = process.cwd();
+    process.chdir(tmpDir);
+  });
+
+  afterEach(() => {
+    process.chdir(prevCwd);
+    process.exitCode = 0;
+    rmSync(tmpDir, { recursive: true, force: true });
+  });
+
+  it('requires --project', async () => {
+    const cmd = createConfigCommand(
+      { configDeps: { configDir: tmpDir }, log },
+      { client, credentialsDeps: { configDir: tmpDir }, log },
+    );
+    await cmd.parseAsync(['prime-agent', '--skip-skills'], { from: 'user' });
+    expect(output.join('\n')).toContain('--project is required');
+    expect(process.exitCode).toBe(1);
+  });
+
+  it('writes proxy MCP entry into prime-agent settings.json', async () => {
+    const settingsPath = join(tmpDir, 'settings.json');
+    const cmd = createConfigCommand(
+      { configDeps: { configDir: tmpDir }, log },
+      { client, credentialsDeps: { configDir: tmpDir }, log },
+    );
+    await cmd.parseAsync(['prime-agent', '--project', 'homeautomation', '-o', settingsPath, '--skip-skills'], { from: 'user' });
+
+    const written = JSON.parse(readFileSync(settingsPath, 'utf-8'));
+    expect(written.mcpServers['homeautomation']).toEqual({
+      type: 'http',
+      url: `${DEFAULT_MCPCTL_GATEWAY_URL}/projects/homeautomation/mcp`,
+    });
+    expect(output.join('\n')).toContain('homeautomation');
+  });
+
+  it('merges with existing servers and preserves other settings', async () => {
+    const settingsPath = join(tmpDir, 'settings.json');
+    writeFileSync(settingsPath, JSON.stringify({
+      defaultProvider: 'itaz',
+      mcpServers: {
+        sre: { type: 'http', url: `${DEFAULT_MCPCTL_GATEWAY_URL}/projects/sre/mcp` },
+      },
+    }));
+
+    const cmd = createConfigCommand(
+      { configDeps: { configDir: tmpDir }, log },
+      { client, credentialsDeps: { configDir: tmpDir }, log },
+    );
+    await cmd.parseAsync(['prime-agent', '--project', 'proj-1', '-o', settingsPath, '--skip-skills'], { from: 'user' });
+
+    const written = JSON.parse(readFileSync(settingsPath, 'utf-8'));
+    expect(written.defaultProvider).toBe('itaz'); // untouched
+    expect(written.mcpServers['sre']).toBeDefined(); // preserved
+    expect(written.mcpServers['proj-1']).toEqual({
+      type: 'http',
+      url: `${DEFAULT_MCPCTL_GATEWAY_URL}/projects/proj-1/mcp`,
+    });
+  });
+
+  it('writes a project marker for later skills sync', async () => {
+    const settingsPath = join(tmpDir, 'settings.json');
+    const cmd = createConfigCommand(
+      { configDeps: { configDir: tmpDir }, log },
+      { client, credentialsDeps: { configDir: tmpDir }, log },
+    );
+    await cmd.parseAsync(['prime-agent', '--project', 'sre', '-o', settingsPath, '--skip-skills'], { from: 'user' });
+
+    const markerPath = join(tmpDir, '.mcpctl-project');
+    expect(readFileSync(markerPath, 'utf-8').trim()).toBe('sre');
+  });
+
+  it('--dry-run prints the change without writing', async () => {
+    const settingsPath = join(tmpDir, 'settings.json');
+    const cmd = createConfigCommand(
+      { configDeps: { configDir: tmpDir }, log },
+      { client, credentialsDeps: { configDir: tmpDir }, log },
+    );
+    await cmd.parseAsync(['prime-agent', '--project', 'proj-2', '-o', settingsPath, '--dry-run'], { from: 'user' });
+
+    expect(output.join('\n')).toContain('proj-2');
+    // No file should have been created.
+    expect(exceptionSafeRead(settingsPath)).toBeNull();
+  });
+
+  it('does not call the API when --skip-skills is set', async () => {
+    const settingsPath = join(tmpDir, 'settings.json');
+    const cmd = createConfigCommand(
+      { configDeps: { configDir: tmpDir }, log },
+      { client, credentialsDeps: { configDir: tmpDir }, log },
+    );
+    await cmd.parseAsync(['prime-agent', '--project', 'proj-3', '-o', settingsPath, '--skip-skills'], { from: 'user' });
+
+    expect(client.get).not.toHaveBeenCalled();
+  });
+
+  it('backward compat: prime-agent-generate still works', async () => {
+    const settingsPath = join(tmpDir, 'settings.json');
+    const cmd = createConfigCommand(
+      { configDeps: { configDir: tmpDir }, log },
+      { client, credentialsDeps: { configDir: tmpDir }, log },
+    );
+    await cmd.parseAsync(['prime-agent-generate', '--project', 'proj-1', '-o', settingsPath, '--skip-skills'], { from: 'user' });
+
+    const written = JSON.parse(readFileSync(settingsPath, 'utf-8'));
+    expect(written.mcpServers['proj-1']).toBeDefined();
+  });
+});
+
+function exceptionSafeRead(path: string): string | null {
+  try {
+    return readFileSync(path, 'utf-8');
+  } catch {
+    return null;
+  }
+}