feat: add semantic browser recording via bsk record

[shnpd]

Capture user flows as LLM-readable trace.json (v1) with intent, page context, and semantic targets. Wire record_start/stop/await through CLI, daemon, and extension; bump CLI to 0.1.8 and extension to 0.1.4.

[BB-fat]

Suggestion: Add a recording entry point in the Popup UI (generate a prompt for the Agent)

This PR’s recording capability (bsk record) is primarily meant to be invoked by an Agent via the CLI. There is currently no user-facing entry point in the Extension UI. BrowserSkill itself cannot call a large language model, and end users will not type CLI commands themselves.

Proposal: add a recording-related entry in the Popup, e.g. “Record a flow / Teach the Agent how to do this”:

1. The user clicks the entry in the Popup
2. The extension generates a Prompt that can be pasted directly to an Agent (with one-click copy)
3. The Prompt must include the current BrowserID (instance_id), so the Agent can target the correct browser instance and run bsk record start …
4. The user pastes the Prompt to the Agent → the Agent starts recording → the user demonstrates in the Agent Window → clicks Finish → the Agent receives trace.json

This would turn the collaboration model—“humans only demonstrate; the Agent starts recording and saves the textbook”—from CLI-only documentation into an in-product discovery path, lowering first-time discovery and onboarding cost.

Could this be a follow-up to this PR, or a minimal Popup entry included in this PR?

[BB-fat]

RecordOverlay doesn't match our existing overlay style (ControlOverlay):

• Dark card vs white pill + logo
• Red rectangular button vs orange pill CTA with icon
• No fade-in / breathe treatment

Please align with the existing bottom pill pattern before merge.