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-05.md

@@ -0,0 +1,40 @@
+# Session 05: Subscription Index
+
+## Summary
+
+The subscription list (sublist) — a trie-based data structure for matching NATS subjects to subscriptions. Core to message routing performance.
+
+## Scope
+
+| Go File | Features | Feature IDs | Go LOC |
+|---------|----------|-------------|--------|
+| server/sublist.go | 81 | 3404–3484 | 1,416 |
+| **Total** | **81** | | **1,416** |
+
+## .NET Classes
+
+- `SubscriptionIndex` — trie-based subject matching
+- `SubscriptionIndexResult` — match result container
+- `SublistStats` — statistics for the subscription index
+
+## Test Files
+
+| Test File | Tests | Test IDs |
+|-----------|-------|----------|
+| server/sublist_test.go | 96 | 2962–3057 |
+| **Total** | **96** | |
+
+## Dependencies
+
+- Session 01 (Foundation Types)
+- Session 02 (Utilities — subject parsing helpers)
+
+## .NET Target Location
+
+- `dotnet/src/ZB.MOM.NatsNet.Server/Internal/DataStructures/SubscriptionIndex.cs`
+
+## Notes
+
+- Performance-critical: hot path for every message published
+- Use `ReadOnlySpan<byte>` for subject matching on hot paths
+- The existing `SubjectTree` (already ported in stree module) is different from this — sublist is the subscription matcher