Add module-aware go-to-definition

[nickna]

Part of #1306.

Summary:

• preserve independent value and type binding identities through module exports, imports, aliases, and re-exports
• resolve definitions against the real module graph with dirty open-document overlays and disk fallback
• retain named type tokens for type-space navigation while leaving qualified property/member navigation unsupported
• keep valid local definitions available when unrelated imports fail to resolve
• update the LSP roadmap and add focused language-server coverage

Testing:

• dotnet build SharpTS.sln --no-restore
• dotnet test SharpTS.Tests/SharpTS.Tests.csproj --no-restore --filter FullyQualifiedName~DefinitionServiceTests (17 passed)
• dotnet test SharpTS.Tests/SharpTS.Tests.csproj --no-restore (16,222 passed)