Further work on Golang RPC, import manipulation, and formatting

[jkschneider]

Summary

Brings rewrite-go to parity with the JavaScript / Python / C# language ports across the RPC handler surface, recipe-author primitives, type attribution, test harness, and recipe library.

RPC handler surface

• Parse / ParseProject (project-aware: module + goModContent; per-file closest-ancestor go.mod ownership; sibling go.sum populates ResolvedDependencies).
• BatchVisit returns {modified, deleted, hasNewMessages, searchResultIds}; searchResultIds walker registered, hasNewMessages snapshot tracked.
• Generate drives ScanningRecipe.Generate.
• GetMarketplace emits the full descriptor (recipeList, dataTables, preconditions, maintainers, contributors, examples, option types).
• PrepareRecipe returns per-instance UUID.
• TraceGetObject for RPC tracing.
• Server CLI flags: --log-file, --trace-rpc-messages, --metrics-csv, --recipe-install-dir, --data-tables-csv-dir.

Recipe-author surface

• recipe.Recipe + recipe.Base; ScanningRecipe end-to-end.
• recipe.DataTable[Row] generic + InMemoryDataTableStore + CsvDataTableStore.
• visitor.GoVisitor.Cursor() / SetCursor(); visitor.BuildChain reconstructs cursors from RPC IDs.
• Cursor message map: PutMessage, GetNearestMessage, PollNearestMessage, etc.
• recipe.Service[T](sourceFile) registry + GoVisitor.DoAfterVisit composition.
• Five services: ImportService, AutoFormatService, AnnotationService, WhitespaceValidationService, NamingService.
• Five foundational recipes: AddImport, RemoveImport, RemoveUnusedImports, OrderImports, RenamePackage.

Type attribution

• Same-package multi-file resolution via parser.ParsePackage.
• Third-party module resolution via go.mod requires + vendor walker (real JavaTypeMethod attribution; honors replace directives).
• tree.GoResolutionResult marker (Module, Requires, Replaces, Excludes, Retracts, ResolvedDependencies); both Go-side and Java-side RPC codecs.
• parser.ProjectImporter 3-tier lazy resolver (sources → requires → stdlib).
• Build-tag file inclusion: parser.MatchBuildContext recognizes //go:build, // +build, and filename suffixes.
• Cross-package generics across the corpus.

RPC sender / receiver visitor-pattern refactor

• Senders / receivers on both sides extend the language visitor (visitor.GoVisitor on Go, JavaVisitor<RpcSendQueue/ReceiveQueue> on Java) and override VisitX, mirroring rewrite-java.
• Eliminated ~600 LOC of switch boilerplate.
• tree.J got polymorphic GetID / GetPrefix / GetMarkers; mutators intentionally NOT on the interface (would break RecipeScheduler identity-based change detection).

Annotations

• tree.Annotation (J-shaped) + LeadingAnnotations on VariableDeclarations, MethodDeclaration, TypeDecl on both sides.
• Struct field tags AND //go: / //lint: directives uniformly modeled as J.Annotation.
• AnnotationService surface mirrors rewrite-java.

Test harness

• Java: Assertions.go(...), goMod(...), goProject(name, ...) matching mavenProject(...).
• Go: test.RewriteRun + test.Golang(...), test.GoMod(...), test.GoSum(...), test.GoProject(name, ...).
• propagateModuleResolution copies the parsed go.mod marker onto every sibling .go CU at project expansion.
• ExpectType / ExpectPrimitiveType / ExpectMethodType helpers on both sides.
• GoMod conformance corpus (10 cases) shared across Go + Java tests.
• Printer parity corpus (13 fixtures across gofmt/ + generics/), opt-in via make parity, never in CI.

Documentation

• Recipe-author guide at doc/recipe-authoring.md.
• PLAN.md removed; contents now reflected in the codebase, doc, and shipped tests.

Test plan

• cd rewrite-go && go test ./... — full Go suite green.
• ./gradlew :rewrite-go:check :rewrite-go:integTest — Java unit + integ.
• cd rewrite-go && make parity — printer corpus byte-equality.
• Downstream: recipes-go test suite against the worktree replace path.