Document the complete FixMap feature set and v0.8.8 launch posts

[aryamthecodebreaker]

Summary

• adds a comprehensive README feature catalog across CLI inputs, mapping, ranking, test/risk routing, diagnostics, cache behavior, Plan/Explain/Compare/Verify/Doctor, MCP, GitHub Action, TypeScript library, browser demo, trust boundaries, compatibility, evidence, and website capabilities
• keeps the README scannable at 204 lines instead of restoring the retired 619-line duplication
• adds ready-to-post X and LinkedIn launch copy for v0.8.8

Verification

• X draft: 270 characters
• all website, demo, evidence, and GitHub Release links return HTTP 200
• release claims cross-checked against the completed Publish workflow and issue/test state
• Markdown whitespace check clean