Fix NIP-42 AUTH compliance: always respond with OK message

- Ensure AUTH handler always sends OK response per NIP-42 specification,
  including for parse failures (uses zero event ID with error reason)
- Add zeroEventID constant for OK responses when event ID cannot be parsed
- Document critical client guidance: clients MUST wait for OK response
  after AUTH before publishing events requiring authentication
- Update nostr skill and CLAUDE.md with NIP-42 AUTH protocol requirements
  for client developers, emphasizing OK response handling
- Add MAX_THINKING_TOKENS setting to Claude configuration

Files modified:
- app/handle-auth.go: Add OK response for AUTH parse failures
- .claude/skills/nostr/SKILL.md: Document AUTH OK response requirements
- CLAUDE.md: Add NIP-42 AUTH Protocol section for client developers
- .claude/settings.local.json: Add MAX_THINKING_TOKENS setting
- pkg/version/version: Bump to v0.34.7

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

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

.claude/skills/nostr/SKILL.md

@@ -150,10 +150,20 @@ Event kind `7` for reactions:
 
 #### NIP-42: Authentication
 Client authentication to relays:
-- AUTH message from relay
-- Client responds with event kind `22242`
+- AUTH message from relay (challenge)
+- Client responds with event kind `22242` signed auth event
 - Proves key ownership
 
+**CRITICAL: Clients MUST wait for OK response after AUTH**
+- Relays MUST respond to AUTH with an OK message (same as EVENT)
+- An OK with `true` confirms the relay has stored the authenticated pubkey
+- An OK with `false` indicates authentication failed:
+  1. **Alert the user** that authentication failed
+  2. **Assume the relay will reject** subsequent events requiring auth
+  3. Check the `reason` field for error details (e.g., "error: failed to parse auth event")
+- Do NOT send events requiring authentication until OK `true` is received
+- If no OK is received within timeout, assume connection issues and retry or alert user
+
 #### NIP-50: Search
 Query filter extension for full-text search:
 - `search` field in REQ filters