Build Creator Data Bridge MVP foundation

[Hol-ick]

Summary

• establish the Chrome MV3, Fastify, and shared-contract monorepo foundation
• implement the YouTube analytics vertical slice and local OAuth/token handling
• define the local-first TikTok, Instagram, and X CSV collection architecture
• document the future official-API publishing path
• add public repository governance, contribution, security, and MIT licensing files

Verification

• pnpm check
• relative Markdown link validation
• git diff --check

Current status

This PR remains draft while the CSV collection extension is implemented. The next code slice is collection contracts, normalization, and deterministic CSV export.