Release v0.12.2: recoverable passwords and portable relay

[TeoSlayer]

Summary

• add owner-local password retrieval and live password rotation without restarting the terminal
• prevent stale browser credentials, removed-member shares, and cross-organization team state from surviving security changes
• harden session assignment handoffs, CLI callbacks, browser policy, key validation, and PTY dimensions
• add the portable standalone relay and versioned self-hosting documentation
• restore the platform matrix, Star History, and contributor visibility in the concise README
• prepare the v0.12.2 website, Docker, documentation, and CLI artifacts

Deployment order

1. accounts app backend and web
2. relay and website Worker
3. v0.12.2 CLI release

No database migration is introduced by this change.

Validation

• npm run check
• go test -race ./... -count=1 -timeout=5m
• app: npm run typecheck && npm test (820 passed, 3 skipped)
• production app build with the configured Firebase client variables
• npm run build and 78 release-file checksum verification
• dependency and secret scans

Closes #67
Closes #84