feat(cli): add agent stop command

Implements the `agent stop` command for stopping agents.

Features:
- Stop a specific agent by ID (with prefix matching)
- --all flag to stop all running agents
- --cwd flag to stop all agents in a specific directory
- Cancels running agents before terminating them
- Graceful error handling for partially failed stops

Usage:
  paseo agent stop <id>
  paseo agent stop --all
  paseo agent stop --cwd ~/dev/paseo

packages/cli/tests/07-agent-stop.test.mts

@@ -0,0 +1,136 @@
+#!/usr/bin/env npx tsx
+
+/**
+ * Phase 6: Agent Stop Command Tests
+ *
+ * Tests the agent stop command - stopping agents (cancel if running, then terminate).
+ * Since daemon may not be running, we test both:
+ * - Help and argument parsing
+ * - Graceful error handling when daemon not running
+ * - All flags are accepted
+ *
+ * Tests:
+ * - agent stop --help shows options
+ * - agent stop requires ID, --all, or --cwd
+ * - agent stop handles daemon not running
+ * - agent stop --all flag is accepted
+ * - agent stop --cwd flag is accepted
+ */
+
+import assert from 'node:assert'
+import { $ } from 'zx'
+import { mkdtemp, rm } from 'fs/promises'
+import { tmpdir } from 'os'
+import { join } from 'path'
+
+$.verbose = false
+
+console.log('=== Agent Stop Command Tests ===\n')
+
+// Get random port that's definitely not in use (never 6767)
+const port = 10000 + Math.floor(Math.random() * 50000)
+const paseoHome = await mkdtemp(join(tmpdir(), 'paseo-test-home-'))
+
+try {
+  // Test 1: agent stop --help shows options
+  {
+    console.log('Test 1: agent stop --help shows options')
+    const result = await $`npx paseo agent stop --help`.nothrow()
+    assert.strictEqual(result.exitCode, 0, 'agent stop --help should exit 0')
+    assert(result.stdout.includes('--all'), 'help should mention --all flag')
+    assert(result.stdout.includes('--cwd'), 'help should mention --cwd option')
+    assert(result.stdout.includes('--host'), 'help should mention --host option')
+    assert(result.stdout.includes('[id]'), 'help should mention optional id argument')
+    console.log('✓ agent stop --help shows options\n')
+  }
+
+  // Test 2: agent stop requires ID, --all, or --cwd
+  {
+    console.log('Test 2: agent stop requires ID, --all, or --cwd')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop`.nothrow()
+    assert.notStrictEqual(result.exitCode, 0, 'should fail without id, --all, or --cwd')
+    const output = result.stdout + result.stderr
+    const hasError =
+      output.toLowerCase().includes('missing') ||
+      output.toLowerCase().includes('required') ||
+      output.toLowerCase().includes('argument') ||
+      output.toLowerCase().includes('id')
+    assert(hasError, 'error should mention missing argument')
+    console.log('✓ agent stop requires ID, --all, or --cwd\n')
+  }
+
+  // Test 3: agent stop handles daemon not running
+  {
+    console.log('Test 3: agent stop handles daemon not running')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop abc123`.nothrow()
+    // Should fail because daemon not running
+    assert.notStrictEqual(result.exitCode, 0, 'should fail when daemon not running')
+    const output = result.stdout + result.stderr
+    const hasError =
+      output.toLowerCase().includes('daemon') ||
+      output.toLowerCase().includes('connect') ||
+      output.toLowerCase().includes('cannot')
+    assert(hasError, 'error message should mention connection issue')
+    console.log('✓ agent stop handles daemon not running\n')
+  }
+
+  // Test 4: agent stop --all flag is accepted
+  {
+    console.log('Test 4: agent stop --all flag is accepted')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop --all`.nothrow()
+    const output = result.stdout + result.stderr
+    assert(!output.includes('unknown option'), 'should accept --all flag')
+    assert(!output.includes('error: option'), 'should not have option parsing error')
+    console.log('✓ agent stop --all flag is accepted\n')
+  }
+
+  // Test 5: agent stop --cwd flag is accepted
+  {
+    console.log('Test 5: agent stop --cwd flag is accepted')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop --cwd /tmp`.nothrow()
+    const output = result.stdout + result.stderr
+    assert(!output.includes('unknown option'), 'should accept --cwd flag')
+    assert(!output.includes('error: option'), 'should not have option parsing error')
+    console.log('✓ agent stop --cwd flag is accepted\n')
+  }
+
+  // Test 6: agent stop with ID and --host flag is accepted
+  {
+    console.log('Test 6: agent stop with ID and --host flag is accepted')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo agent stop abc123 --host localhost:${port}`.nothrow()
+    const output = result.stdout + result.stderr
+    assert(!output.includes('unknown option'), 'should accept --host flag')
+    assert(!output.includes('error: option'), 'should not have option parsing error')
+    console.log('✓ agent stop with ID and --host flag is accepted\n')
+  }
+
+  // Test 7: agent shows stop in subcommands
+  {
+    console.log('Test 7: agent --help shows stop subcommand')
+    const result = await $`npx paseo agent --help`.nothrow()
+    assert.strictEqual(result.exitCode, 0, 'agent --help should exit 0')
+    assert(result.stdout.includes('stop'), 'help should mention stop subcommand')
+    console.log('✓ agent --help shows stop subcommand\n')
+  }
+
+  // Test 8: -q (quiet) flag is accepted with agent stop
+  {
+    console.log('Test 8: -q (quiet) flag is accepted with agent stop')
+    const result =
+      await $`PASEO_HOST=localhost:${port} PASEO_HOME=${paseoHome} npx paseo -q agent stop abc123`.nothrow()
+    const output = result.stdout + result.stderr
+    assert(!output.includes('unknown option'), 'should accept -q flag')
+    assert(!output.includes('error: option'), 'should not have option parsing error')
+    console.log('✓ -q (quiet) flag is accepted with agent stop\n')
+  }
+} finally {
+  // Clean up temp directory
+  await rm(paseoHome, { recursive: true, force: true })
+}
+
+console.log('=== All agent stop tests passed ===')