fix(sem): extract TypeScript bodyless declarations (overloads, ambients)

[suhaanthayyil]

https://entire.io/gh/entireio/entire-graph/trails/33

The bug

entityFromNode gated both function_signature and method_signature to Dart, with the comment that TypeScript uses those node types for interface members. That is only half true.

tree-sitter-typescript emits function_signature for every bodyless function declaration — overload signatures, declare function, ambients, .d.ts — and method_signature for class-body overload declarations as well as interface members. All of them were silently dropped from the graph.

Concretely, vue's renderList.ts has five overload signatures plus one implementation. It exposed 1 symbol, covering only the implementation's lines. Lines 10–53 — the entire typed surface — were unindexed, so no query phrased in terms of the declared parameter types could retrieve the file. After the fix: 6 symbols.

The fix

Additive, +54 lines, no deletions, narrowly gated:

• function_signature in TypeScript becomes a function (or a method when scoped). An overload set is where the parameter types and generics live; the implementation's own signature is usually the erased (source: any, ...) catch-all.
• method_signature becomes a method only inside a class_body, via the new typeScriptClassBodySignature helper.

Interface and type-literal members deliberately stay inventory-only. They declare a contract, not a definition, and emitting them would make every x.m() call name-resolvable to a bodyless interface member. That is not hypothetical — extending this case to interface_body/object_type members fabricates a CALLS edge in TestTypeScriptNamespaceCallSkipsParameterReceiverRoots, where a parameter named B shadows a namespace and B.parse() then binds to Client.parse instead of correctly resolving to nothing.

Dart behaviour is unchanged — the existing Dart paths are reached only when the language is not TypeScript.

Verification

• Full internal/sem suite green (1976 tests).
• New regression test parser_typescript_regression_test.go (+124 lines) covering overload sets, declare function, class-body overloads, and the interface-member exclusion.
• Attribution check: symbol output is byte-identical to the pre-fix binary on eight non-TypeScript repositories — django, axum, gson, carbon, bat, caddy, fmt, rubocop. So the change is attributable to TypeScript alone and cannot perturb other languages.

Scope note

Repo-wide symbol gain is modest (vuejs +1.0%, docusaurus +2.1%) — this is a correctness fix for a whole class of declarations, not a broad indexing win. Its practical effect is concentrated in TypeScript codebases that use overloads and ambient declarations heavily.

[suhaanthayyil]

Closing as superseded by #82, with a caveat worth recording.

Superseded: #82 contains this PR's four search commits by identical SHA (8d464ce, 5511d6f, afdb54e, afd5a1c) and folds the TypeScript fix into 19b0769. git diff pr79 pr82 -- internal/sem/parser_typescript_regression_test.go is empty and the parser.go hunks are byte-identical; #82's parser.go is a strict superset (it also carries the Go method_elem/method_spec case).

Two reasons not to merge this one on its own, both measured on a 2-file TS repro:

1. It carries the unhardened EG_PRESEARCH path — internal/cli/search.go:254-261 reads a pre-delivered payload with no length check. EG_PRESEARCH=<zero-byte file> entire-graph search --query x returns 0 bytes on stdout, exit 0. fix(cli): three ways search could answer with nothing, silently (supersedes #80) #82 fixes this (8a4ffb3, search.go:310-312).
2. Merging it first makes feat: ship search, compact snapshots, explain, and prose-memory results #84 conflict in internal/sem/search.go (the mergeSameFileSearchSpans call lands in the same SearchRepository stage feat: ship search, compact snapshots, explain, and prose-memory results #84 edits), adding a third source of the fix(cli): three ways search could answer with nothing, silently (supersedes #80) #82↔feat: ship search, compact snapshots, explain, and prose-memory results #84 conflict while contributing nothing fix(cli): three ways search could answer with nothing, silently (supersedes #80) #82 lacks.

The TypeScript regression tests here are genuine and verified fail-without/pass-with — they live on in #82.

Separately: the same TS change causes compound-v1 ID churn and a fast-profile CALLS loss in both this PR and #82. Being fixed on #82 before it merges.