fix(go): attribute calls inside top-level closures to the var, not the file (#693) (#744)

A function called only from an anonymous func_literal at package level — a
cobra `RunE: func(){…}` handler, a goroutine literal, a callback closure
stored in a `var` — had its call leak to the FILE node, because the Go
var-initializer walk ran with an empty scope. So `callers`/`impact` showed
the function with a file (or no meaningful) caller, unlike JS/TS where an
arrow-in-const becomes a named node whose calls attribute correctly.

Scope the Go top-level var/const initializer walk to the declared symbol, so
a call nested in any func_literal initializer (struct field, slice/map,
nested closure) attributes to the enclosing var. EXTRACTION_VERSION 3->4
(re-index to pick up the corrected attribution).

Validated on cli/cli (858 Go files): node/edge counts identical, file-level
dependents byte-identical (no regression), and 62 top-level-closure calls
correctly moved from file-attributed to var-attributed.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -29,6 +29,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### Fixes
 
+- Go: a function called only from inside an anonymous closure — a cobra `RunE: func(…) {…}` handler, a goroutine literal, or a callback closure stored in a package-level `var` — now shows its real caller. Previously the call leaked to the file node, so `codegraph_callers` and `codegraph_impact` reported such a function as having no meaningful caller; the call is now attributed to the enclosing declaration, so editing the function surfaces the closures that use it. Existing Go indexes should be re-indexed (`codegraph index -f`) to benefit. Thanks @Cyclone1070. (#693) (Go)
 - Indexing no longer aborts when a `.gitignore` contains non-UTF-8 bytes or an unparseable pattern. A `.gitignore` transparently encrypted in place by corporate DLP / endpoint-security software (a common enterprise scenario) — or one with a stray pattern the matcher can't compile (`\[`, producing "Unterminated character class") — used to crash the entire `sync` / `index` with a screen of garbled bytes and never name the offending file, leaving `Files: 0 / Nodes: 0`. CodeGraph now skips a `.gitignore` that isn't valid UTF-8 text whole, drops only the individual unparseable patterns from a text one, and logs a warning naming the file — indexing continues either way. Thanks @zhanghang-9527. (#682)
 - C++ method calls made through a singleton, factory, or chained getter now resolve to the correct class. A call like `Foo::instance().bar()`, `WidgetFactory::create().draw()`, `openSession()->run()`, or the same stored in an `auto` local first, used to lose the receiver's type — so when two classes had a same-named method the call silently attached to whichever was indexed first (or didn't resolve at all), corrupting callers, impact, and trace. CodeGraph now infers the receiver's type from what the inner call returns (capturing C++ return types for the first time) and creates the edge only when that class genuinely has the method, so a wrong guess produces no edge instead of a misleading one. Covers singletons and self-returning accessors, factories that return a different type, free-function factories, `make_unique` / `make_shared` / `new` / direct construction, and single-level member chains. Existing C/C++ indexes should be re-indexed (`codegraph index -f`) to benefit. Thanks @stabey. (#645) (C/C++)
 - The shared background server no longer logs a scary-looking `[error] … undefined` line on every session start. Attaching to the shared daemon is normal, healthy behavior, but the informational message was being surfaced by MCP hosts (Claude Code and others) as an error; it's now silent by default — set `CODEGRAPH_MCP_LOG_ATTACH=1` to surface it when debugging daemon attach. Thanks @mturac. (#618)