Notification Center, CI Playwright test and Gov Prop Improvements

[Andre-Diamond]

Notification Center

• Add notification center data model for signer notification settings, email verification tokens, and idempotent notification deliveries.
• Add tRPC notification procedures for signer settings, email verification, and signature reminders.
• Add notification outbox worker, email delivery channel, and reusable email templates.
• Enqueue signature-required notifications for pending transactions and signable payloads.
• Add notification tests for recipient resolution, safe email rendering, description truncation, and transaction/governance signature summaries.

Governance Proposal Data Fetching Improvements

• Improve /api/v1/governanceActiveProposals to fetch proposal details for reliable active-status resolution.
• Add metadata fallback handling for proposal metadata by transaction/cert index and governance action ID.
• Hydrate missing JSON metadata from anchor URLs, including IPFS gateway fallbacks.
• Add direct Blockfrost REST fallback when provider construction or provider calls fail without a provider status.
• Add tests covering active proposal filtering, metadata 404 tolerance, optional detail failures, empty proposal lists, and provider fallback paths.

Playwright Browser Coverage

• Add Playwright browser test stack using docker-compose.playwright.yml.
• Add CI workflow .github/workflows/pr-playwright-browser.yml for PR browser tests.
• Add full browser-driven ring transfer test covering legacy, hierarchical, and SDK wallet types.
• Validate transaction creation, second-signer approval, broadcast success, and pending transaction cleanup.
• Upload Playwright reports, traces, and sanitized container logs for CI diagnostics.

CI smoke test bug fixes

• Fixed bootstrap bug that generated wrong wallet address