feat: Add video recording with Playwright native video (#116)

* feat: add video recording with Playwright native video

Adds `record start/stop` commands using Playwright's built-in video
recording. No external dependencies required (no FFmpeg).

Usage:
  agent-browser record start ./demo.webm https://example.com
  agent-browser click @e1
  agent-browser record stop

Recording creates a fresh browser context with video enabled. For smooth
demos, explore the page first to plan actions, then start recording.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* feat: auto-capture URL and transfer state for recording

When starting a recording without a URL:
- Automatically captures current page URL
- Preserves cookies and localStorage from current session

This enables a seamless workflow:
  agent-browser open https://app.example.com
  agent-browser snapshot -i  # explore, plan
  agent-browser record start ./demo.webm  # picks up URL + auth state
  agent-browser click @e3
  agent-browser record stop

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: error on non-webm recording path instead of silent coercion

Previously, specifying a non-.webm path like ./demo.mp4 would silently
change it to ./demo.webm. Now it throws a clear error telling the user
that Playwright native recording only supports WebM format.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: clean up recording temp directory after stopRecording

Previously the temp directory was created but never deleted, relying on
OS cleanup. Now we explicitly remove it after saving the video, in both
success and error paths.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* feat: add record restart command

Adds `record restart` command that stops the current recording (if any)
and starts a new one. Also improves the error message when trying to
start recording while already recording.

Changes:
- Add restartRecording method to BrowserManager
- Add recording_restart action to protocol, types, and actions
- Add CLI parsing for `record restart <path> [url]`
- Update help text and skill documentation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* test: add CLI tests for record restart command

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Chris Tate <chris@ctate.dev>

skills/agent-browser/SKILL.md

@@ -90,6 +90,15 @@ agent-browser screenshot --full   # Full page
 agent-browser pdf output.pdf      # Save as PDF
 ```
 
+### Video recording
+```bash
+agent-browser record start ./demo.webm    # Start recording (uses current URL + state)
+agent-browser click @e1                   # Perform actions
+agent-browser record stop                 # Stop and save video
+agent-browser record restart ./take2.webm # Stop current + start new recording
+```
+Recording creates a fresh context but preserves cookies/storage from your session. If no URL is provided, it automatically returns to your current page. For smooth demos, explore first, then start recording.
+
 ### Wait
 ```bash
 agent-browser wait @e1                     # Wait for element
@@ -225,6 +234,11 @@ agent-browser get text @e1 --json
 ## Debugging
 
 ```bash
+agent-browser open example.com --headed              # Show browser window
+agent-browser console                                # View console messages
+agent-browser errors                                 # View page errors
+agent-browser record start ./debug.webm   # Record from current page
+agent-browser record stop                            # Save recording
 agent-browser open example.com --headed  # Show browser window
 agent-browser --cdp 9222 snapshot        # Connect via CDP
 agent-browser console                    # View console messages