Prepare repository for external review

[ael-dev3]

Summary

• replace duplicated release/process prose with a concise changelog, current architecture overview, roadmap, versioning guide, and documentation index
• remove the unreachable pre-Spacetime prototype and its unused CSS while preserving every generic rule inherited by the live UI
• add professional package metadata, a single contributor check command, EditorConfig, and narrowly fingerprinted historical secret-scan exceptions
• remove obsolete hard-coded Alpha 0.2 workflow bases while keeping Verify and CodeQL active for every pull request, including stacked drafts

This reduces tracked Markdown/text from 10,587 to 6,963 lines and removes roughly 4,900 net lines without changing current gameplay, authentication, database authority, runtime assets, or production operations.

Scope boundaries

• no files under services/auth-bridge/** or spacetimedb/** changed
• no operator scripts, generated bindings, production configuration, runtime assets, admissions, data, deployment, or open feature PRs changed
• detailed historical release notes remain available through tags, GitHub Releases, merged PRs, and commit history

Validation

• final-head npm run check
  • license attestation passed
  • 34 runtime assets and 4 provenance masters verified
  • file-size policy passed
  • 145 test files / 1,459 tests passed
  • typecheck and production build passed
  • local QA routes and broker markers excluded from production output
• full-history secret scan: 197 commits, no leaks
• current-tree secret scan: no leaks
• relative Markdown targets and code fences checked
• local title/menu visual pass completed with no browser console warnings or errors
• independent final review found no remaining blocker

Drafted deliberately for external review before merge.

[ael-dev3]

Superseded by the audited Alpha 0.3.11 integration in #64, now merged to protected main. Accepted work was reconciled, corrected where needed, and validated there; this original branch is intentionally not merged again.