feat: add annotation audit mode and a local CI tool

[vamgan]

Summary

Add an annotation-quality audit mode and local CI tool that tells developers whether their Askable context is useful, safe, stable, and within budget.

Proposed UX

<AskableInspector audit={{
  sensitiveKeys: ['email', 'token', 'secret'],
  maxElementTokens: 200,
  requireStableIds: true,
}} />

npx askable audit http://localhost:3000   --journey ./askable.journey.ts   --format json   --fail-on error

Diagnostics

• malformed metadata
• unstable or non-unique selectors/IDs
• suspicious sensitive keys and unredacted packet fields
• empty or flattened/noisy text
• excessive token cost
• missing accessible labels
• important interactive regions without annotations
• chart/table regions that should use curated data-askable-text

Acceptance criteria

• Inspector highlights offending elements and recommends concrete fixes
• CLI emits stable machine-readable diagnostics with severity and selector
• CI thresholds can fail builds
• Reports context coverage and token distribution across a journey
• Runs entirely locally without uploading page content
• Supports at least React/Vite and Next.js examples initially
• Integrates privacy-policy findings from bug(mcp): WebContextPacket serialized to agent without verifying redaction was applied #274 rather than implementing competing rules