add support for nip-05 filters

[alltheseas]

Summary

• Added support for nip05 filters end-to-end: profile ingestion now
  normalizes/records NIP‑05 domains, the new NDB_FILTER_NIP05 plan walks
  the index, and ndb_note_matches_nip05_filter revalidates query hits.
• Exercised the feature with test_nip05_domain_query, covering domain
  case-folding, reassignments, and “no match” results; beefed up the
  harness so test_timeline_query repopulates the contact authors after
  the NIP‑05 test wipes the LMDB.
• Cleaned up small helpers (comparators, etc.) per the never-nesting
  guideline so the code style is in line with the rest of the branch.
• Should close NIP-05 filtering to allow for e.g. nostr address feed #82

Testing

• LSAN_OPTIONS=detect_leaks=0 make check (fails at upstream
  test_delete_e_tag due to existing filter-state bug; unrelated to this
  PR)

[alltheseas]

@tyiu :eyes