feat(mcp): expose decision-pack and doctor resources

[JSONbored]

Parent roadmap: #127
Parent phase: #269
Parent epic: #273

Goal

Expose decision-pack and doctor/status state through MCP resources instead of only command-style tools.

Requirements

• Add discoverable resources for decision packs, doctor/status state, compatibility metadata, and release/changelog state where appropriate.
• Keep resource content bounded and public/private aware.
• Preserve source-upload fail-closed behavior.

Acceptance criteria

• MCP clients can discover and read the new resources.
• Resource output does not expose private data unless the authenticated surface already allows it.
• Existing tool behavior remains intact.
• This is not public scoring or autonomous GitHub action.

Validation expected

• MCP resource discovery and read tests.
• npm run build:mcp.
• npm run test:mcp-pack.
• npm run test:ci.