fix(go): field-chain calls resolve via validated type inference, never bare-name guessing (#1316)

target.conn.Exec("insert") with `conn *sql.DB` emitted a BARE `Exec`
ref (the receiver chain was dropped for non-identifier receivers), and
exact-match then bound it to the only local `Exec` — an unrelated
interface's method — fabricating an internal dependency (#1276).

Extraction now keeps Go 2-hop selector chains (`base.field.Method`),
and a dedicated matcher resolves them EXCLUSIVELY via two inference
hops: base's type from the enclosing scope (#1108 machinery), field's
declared type from the struct's own declaration lines (comment-
stripped, per-line — chi's "the tree router" doc comment otherwise
donates a phantom type). resolveMethodOnType validates the target.
Package-qualified field types are followed only when the package is
in-module — `handler http.Handler` must not bind a same-named local
decoy. Failure at any hop leaves the ref unresolved: chained Go
receivers never fall through to the bare-name strategies (they were
never emitted before, so no prior recall depends on that path).

chi before/after: node count stable (1,181); 8 correct field-chain
edges gained (mx.tree.FindRoute/InsertRoute/routes, validated,
including the unexported `node` type); the removed edges are the
prior bare-name guesses on external receivers.

Fixes #1276

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -18,6 +18,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### Fixes
 
+- Go method calls through a struct field (`target.conn.Exec(...)`) no longer bind to unrelated same-named local methods when the field's type is external — `conn *sql.DB` calls were being attributed to a local interface that happened to declare `Exec`, fabricating internal dependencies. Chained field calls now resolve by inferring the field's declared type from the struct definition: in-project types (including unexported ones like chi's `tree *node`) gain correct, validated call edges that never existed before, and external types (standard library, third-party modules) are left unlinked instead of guessed. (#1276)
 - TypeScript/JavaScript method calls through an imported singleton (`import { store } from './store'; store.notify()`) now resolve to the class method instead of the exported constant, so `codegraph callers` sees cross-file callers of the method — previously only same-file calls were attributed and a method used everywhere could look unused. The same declaration-based type inference applies across the languages that share it (Python, Java, Kotlin, Go, and more), and a failed inference keeps the old edge rather than guessing. (#1292)
 - `codegraph node <symbol> -f <file>` now prints the symbol's source body. Pinning an ambiguous name to a specific file (the whole point of `-f` when many files define the same function) returned only the location and caller trail with no code. (#1284)
 - Deleting a whole directory is now picked up by watch mode: the files inside it are removed from the index on the next auto-sync instead of lingering as stale records until an unrelated edit happened to trigger one. Operating systems often report a directory deletion as a single event on the directory itself (with no per-file events for its contents), which the watcher previously discarded. (#1285)