Add Neo4j memory tuning config and query result limits (v0.43.0)

- Add Neo4j driver config options for memory management:
  - ORLY_NEO4J_MAX_CONN_POOL (default: 25) - connection pool size
  - ORLY_NEO4J_FETCH_SIZE (default: 1000) - records per batch
  - ORLY_NEO4J_MAX_TX_RETRY_SEC (default: 30) - transaction retry timeout
  - ORLY_NEO4J_QUERY_RESULT_LIMIT (default: 10000) - max results per query
- Apply driver settings when creating Neo4j connection (pool size, fetch size, retry time)
- Enforce query result limit as safety cap on all Cypher queries
- Fix QueryForSerials and QueryForIds to preserve LIMIT clauses
- Add comprehensive memory tuning documentation with sizing guidelines
- Add NIP-46 signer-based authentication for bunker connections
- Update go.mod with new dependencies

Files modified:
- app/config/config.go: Add Neo4j driver tuning config vars
- main.go: Pass new config values to database factory
- pkg/database/factory.go: Add Neo4j tuning fields to DatabaseConfig
- pkg/database/factory_wasm.go: Mirror factory.go changes for WASM
- pkg/neo4j/neo4j.go: Apply driver config, add getter methods
- pkg/neo4j/query-events.go: Enforce query result limit, fix LIMIT preservation
- docs/NEO4J_BACKEND.md: Add Memory Tuning section, update Docker example
- CLAUDE.md: Add Neo4j memory tuning quick reference
- app/handle-req.go: NIP-46 signer authentication
- app/publisher.go: HasActiveNIP46Signer check
- pkg/protocol/publish/publisher.go: NIP46SignerChecker interface
- go.mod: Add dependencies

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -46,6 +46,14 @@ NOSTR_SECRET_KEY=nsec1... ./nurl https://relay.example.com/api/logs/clear
 | `ORLY_TLS_DOMAINS` | | Let's Encrypt domains |
 | `ORLY_AUTH_TO_WRITE` | false | Require auth for writes |
 
+**Neo4j Memory Tuning** (only when `ORLY_DB_TYPE=neo4j`):
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `ORLY_NEO4J_MAX_CONN_POOL` | 25 | Max connections (lower = less memory) |
+| `ORLY_NEO4J_FETCH_SIZE` | 1000 | Records per batch (-1=all) |
+| `ORLY_NEO4J_QUERY_RESULT_LIMIT` | 10000 | Max results per query (0=unlimited) |
+
 See `./orly help` for all options. **All env vars MUST be defined in `app/config/config.go`**.
 
 ## Architecture