feat: port session 07 — Protocol Parser, Auth extras (TPM/certidp/certstore), Internal utilities & data structures

Session 07 scope (5 features, 17 tests, ~1165 Go LOC):
- Protocol/ParserTypes.cs: ParserState enum (79 states), PublishArgument, ParseContext
- Protocol/IProtocolHandler.cs: handler interface decoupling parser from client
- Protocol/ProtocolParser.cs: Parse(), ProtoSnippet(), OverMaxControlLineLimit(),
  ProcessPub/HeaderPub/RoutedMsgArgs/RoutedHeaderMsgArgs, ClonePubArg(), GetHeader()
- tests/Protocol/ProtocolParserTests.cs: 17 tests via TestProtocolHandler stub

Auth extras from session 06 (committed separately):
- Auth/TpmKeyProvider.cs, Auth/CertificateIdentityProvider/, Auth/CertificateStore/

Internal utilities & data structures (session 06 overflow):
- Internal/AccessTimeService.cs, ElasticPointer.cs, SystemMemory.cs, ProcessStatsProvider.cs
- Internal/DataStructures/GenericSublist.cs, HashWheel.cs
- Internal/DataStructures/SubjectTree.cs, SubjectTreeNode.cs, SubjectTreeParts.cs

All 461 tests pass (460 unit + 1 integration). DB updated for features 2588-2592 and tests 2598-2614.

docs/plans/phases/phase6sessions/session-23.md

@@ -0,0 +1,52 @@
+# Session 23: WebSocket & OCSP
+
+## Summary
+
+WebSocket transport layer (allows browser clients to connect via WebSocket) and OCSP certificate stapling/checking infrastructure.
+
+## Scope
+
+| Go File | Features | Feature IDs | Go LOC |
+|---------|----------|-------------|--------|
+| server/websocket.go | 38 | 3506–3543 | 1,265 |
+| server/ocsp.go | 20 | 2443–2462 | 880 |
+| server/ocsp_peer.go | 9 | 2463–2471 | 356 |
+| server/ocsp_responsecache.go | 30 | 2472–2501 | 461 |
+| **Total** | **97** | | **2,962** |
+
+## .NET Classes
+
+- `WebSocketHandler` — WebSocket upgrade and frame handling
+- `WsReadInfo` — WebSocket read state
+- `SrvWebsocket` — WebSocket server configuration
+- `OcspHandler` — OCSP stapling orchestrator
+- `OCSPMonitor` — background OCSP response refresher
+- `NoOpCache` — no-op OCSP cache implementation
+
+## Test Files
+
+| Test File | Tests | Test IDs |
+|-----------|-------|----------|
+| server/websocket_test.go | 109 | 3074–3182 |
+| server/certstore_windows_test.go | 4 | 155–158 |
+| **Total** | **113** | |
+
+## Dependencies
+
+- Session 01 (Foundation Types)
+- Session 08 (Client Connection)
+- Session 09 (Server Core Part 1)
+- Leaf module: certidp (already complete)
+- Leaf module: certstore (already complete)
+
+## .NET Target Location
+
+- `dotnet/src/ZB.MOM.NatsNet.Server/WebSocket/`
+- `dotnet/src/ZB.MOM.NatsNet.Server/Auth/Ocsp/`
+
+## Notes
+
+- WebSocket maps to ASP.NET Core WebSocket middleware or `System.Net.WebSockets`
+- OCSP integrates with the already-ported certidp and certstore modules
+- WebSocket test file has 109 tests — covers masking, framing, compression, upgrade
+- OCSP response cache has 30 features — manage certificate stapling lifecycle