feat(extension): add public-safe packet and private blocker actions

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Background

The extension should help users act from GitHub, especially by copying public-safe PR packets and inspecting private blockers without posting anything.

Goal

Let users copy public-safe PR packets and open private blocker details from the extension.

Current Behavior

PR packet generation is primarily MCP/API-oriented.

Desired Behavior

Users can copy a sanitized packet or inspect authenticated private blocker details from a GitHub overlay.

Implementation Requirements

• Reuse the same public-safe packet generator as MCP/API.
• Gate private blockers by auth and role.
• Run copied output through public sanitizer.
• Avoid local source reads in the extension.
• Record redacted product usage events.

Public/Private Output Boundaries

Public GitHub output must never include wallets, hotkeys, payout/reward estimates, raw trust scores, public score estimates, private reviewability, private scoreability context, or farming language. Private API/MCP/control-panel surfaces may show authenticated scoreability, blockers, projections, and evidence, but must not claim guaranteed payout outcomes.

Acceptance Criteria

• Packet text is sanitized.
• Private blocker details require auth.
• No score/reward/wallet/hotkey leakage.
• Tests cover copied output.

Testing Requirements

• npm run test:ci must pass.
• Global coverage must remain at or above 97% for lines, statements, functions, and branches.
• Aim for 98%+ branch coverage locally.
• Add tests for every new branch, fallback path, sanitizer rule, and regression.
• Add invariant/property-style tests when behavior depends on sorting, gating, scoring, source-upload safety, public/private boundaries, or telemetry privacy.
• MCP/local tooling must prove source contents are not uploaded when local metadata is involved.
• Public GitHub output must be tested against forbidden language: wallet, hotkey, raw trust score, payout, reward estimate, farming, private reviewability, and public score estimate.