Harden feedback collector end to end

[HugoMSFT]

Summary

• make SQLite the authoritative feedback store, preserve user edits across collection and Fabric synchronization, and add forward-safe migrations
• secure credentials, request boundaries, remote access, CSV handling, browser rendering, and collector logging
• replace fragile background state with durable cancellable jobs and tighten collection/Fabric error handling
• correct Fabric token packing, canonical ID synchronization, existing-row updates, state conflict handling, and schema migration behavior
• improve packaged-data persistence and legacy migration, remove obsolete integrations/docs, and refresh dependencies
• prioritize SQL Server and Azure SQL sources and keywords; add public Hacker News and DEV Community collectors plus SQL-focused Stack Exchange and GitHub defaults
• support multiple Reddit communities with normalized comma/newline input, saved-setting migration, validation, sort/time filters, and fair item-limit distribution
• skip missing credential-dependent sources and isolate source failures so successful public-source results are retained
• add cross-platform CI plus regression coverage for routes, persistence, security, jobs, Fabric SQL, collectors, frontend behavior, and packaging paths

Validation

• python -m unittest discover -s tests -v — 88 tests pass
• Python compilation, JavaScript parsing, and diff whitespace checks pass
• live Hacker News, DEV Community, and Stack Overflow API smoke tests pass
• live application collection completed with Hacker News and DEV Community results
• PyInstaller distribution builds successfully
• frozen Windows application responds over loopback, uses per-user application data, and excludes .env