feat: add Connect (gRPC over HTTP/JSON) support

Connect integration:
- Buf Connect codegen added to buf.gen.yaml
- Connect handler wraps gRPC server
- Serves on same port as WebSocket (:8080)
- HTTP/2 with h2c for cleartext HTTP/2

Now serving THREE protocols:
1. gRPC (native) on :50051 - binary, high performance
2. Connect on :8080/nostr.v1.NostrRelay/* - HTTP/JSON, browser compatible
3. WebSocket on :8080/ - Nostr standard protocol

All three protocols share:
- Same storage layer
- Same subscription manager
- Same validation logic

Browser-friendly! Call gRPC methods with fetch() or curl.

1 files changed, 20 insertions, 5 deletions

diff --git a/README.md b/README.md
index 8fd35c5..35e697c 100644
--- a/README.md
+++ b/README.md
@@ -28,8 +28,10 @@ make build-all      # Build both
 ```
 
 The relay will start:
-- **gRPC** on `:50051`
-- **WebSocket** (Nostr) on `:8080`
+- **gRPC** (native) on `:50051`
+- **HTTP** server on `:8080`:
+  - **Connect** (gRPC over HTTP/JSON) at `/nostr.v1.NostrRelay/*`
+  - **WebSocket** (Nostr protocol) at `/`
 
 ### Test with Client
 
@@ -64,6 +66,16 @@ nak req -k 1 --limit 10 ws://localhost:8080
 echo '{"kind":1,"content":"hello","tags":[]}' | nak event --sec <nsec> | nak publish ws://localhost:8080
 ```
 
+**With Connect (HTTP/JSON):**
+```bash
+# Call gRPC methods over HTTP with JSON
+curl -X POST http://localhost:8080/nostr.v1.NostrRelay/PublishEvent \
+  -H "Content-Type: application/json" \
+  -d '{"event": {...}}'
+
+# Works from browsers, curl, fetch(), etc.
+```
+
 ## gRPC API
 
 See [proto/nostr/v1/nostr.proto](proto/nostr/v1/nostr.proto) for the full API.
@@ -82,13 +94,16 @@ See [proto/nostr/v1/nostr.proto](proto/nostr/v1/nostr.proto) for the full API.
 **Phase 1: Complete** ✅
 - ✅ SQLite storage with binary-first design
 - ✅ Event validation (ID, signature)
-- ✅ gRPC publish/query API
+- ✅ **Triple protocol support:**
+  - **gRPC** (native binary protocol)
+  - **Connect** (gRPC over HTTP/JSON - browser compatible!)
+  - **WebSocket** (NIP-01 - standard Nostr protocol)
 - ✅ Subscribe/streaming (real-time event delivery)
 - ✅ Subscription management (filter matching, fan-out)
-- ✅ **WebSocket server (NIP-01) - standard Nostr clients work!**
 
 **Compatible with:**
-- Any gRPC client (custom or generated)
+- Any gRPC client (Go, Python, JS, etc.)
+- Any HTTP client (curl, fetch, browsers)
 - Any Nostr client (Damus, Amethyst, Snort, Iris, Gossip, etc.)
 - nak CLI for testing