feat: store repeater-reported node names (/names) and resolve by them

[efiten]

Summary

CoreDrive RX v1.20.0 asks a repeater for its own name (ANON_REQ_TYPE_OWNER) when this instance has none for it, and publishes the answer as NODE_NAME on meshcore/client/{pk}/names. This stores those answers and uses them where a name is resolved.

• 494583b9 Ingestor: new names subtopic, gated on clientNodeNames.enabled (default off). It stores into a new table client_node_names (observations, UNIQUE(target, rx_pubkey, observed_at)).
  • target must be 64 hex.
  • The name is trimmed and rejected when empty, over 31 runes (firmware node_name[32], src/helpers/CommonCLI.h:27), invalid UTF-8, or holding a control character.
  • Retention retention.clientNodeNamesDays (0 = keep).
• ef0a77b7 Server: lookupPrefixes counts candidates in nodes and client_node_names. /api/nodes/resolve and batchResolveHeardKeys (coverage tooltips) both use it.
  • The advert name wins; otherwise the newest client-reported name by observed_at.
  • A prefix matching different pubkeys across the two tables stays ambiguous.
  • Blacklist and hidden name prefixes apply to both sources.
  • A database without the table resolves from nodes alone, and the table is re-probed until the ingestor creates it.
• fab6dc78 Docs: the /regions section named clientRxCoverage.enabled as its switch. The code uses clientRegions.enabled.

Compatibility

• An older CoreDrive never publishes /names: nothing changes for it.
• An older ingestor drops /names silently (no case), so CoreDrive v1.20.0 works against either.
• /api/nodes/resolve keeps its response shape {prefix, pubkey?, name?, ambiguous}.

Performance

lookupPrefixes adds one LIKE prefix% term per key on client_node_names, served by idx_cnn_target(target, observed_at). It is still one query per chunk of 200 keys, which is 400 compound terms, under SQLite's default 500. Covered by TestLookupPrefixesManyKeys (250 keys over two chunks). Not benchmarked: the table holds one row per answer, and the expected size is in the hundreds.

Trust

Any companion the broker lets publish can report a name for any repeater, and the newest report wins. That is the same model as /regions. clientRxCoverage.requireLinkedCompanion limits it to linked companions.

Test plan

• go test ./... in cmd/ingestor and cmd/server: pass
• New tests: handler, validation cases, idempotent redelivery, newest observed_at wins, prune, gate on/off without observer-path fall-through, client-only node, nameless nodes row, advert name wins, cross-source ambiguity, hidden, blacklisted, absent-then-created table
• Staging: clientNodeNames.enabled, a real /names message, /api/nodes/resolve and a coverage tooltip in the browser
• Not run: frontend unit tests and E2E (no frontend change)

Upstream: fork-only for now. A clean PR against upstream/master comes later.