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-03.md

@@ -0,0 +1,37 @@
+# Session 03: Configuration & Options
+
+## Summary
+
+The server options/configuration system. Parses config files, command-line args, and environment variables into the `ServerOptions` struct. This is large (5.4K LOC) but self-contained.
+
+## Scope
+
+| Go File | Features | Feature IDs | Go LOC |
+|---------|----------|-------------|--------|
+| server/opts.go | 86 | 2502–2587 | 5,400 |
+| **Total** | **86** | | **5,400** |
+
+## .NET Classes
+
+- `ServerOptions` — all configuration properties, parsing, validation, and defaults
+
+## Test Files
+
+| Test File | Tests | Test IDs |
+|-----------|-------|----------|
+| server/opts_test.go | 86 | 2512–2597 |
+| server/config_check_test.go | 3 | 271–273 |
+| **Total** | **89** | |
+
+## Dependencies
+
+- Session 01 (Foundation Types — constants, errors)
+
+## .NET Target Location
+
+- `dotnet/src/ZB.MOM.NatsNet.Server/ServerOptions.cs`
+
+## Notes
+
+- This is a large flat file. Consider splitting `ServerOptions` into partial classes by concern (TLS options, cluster options, JetStream options, etc.)
+- Many options have default values defined in `const.go` (Session 01)