fix(cpp): extract out-of-line member definitions

[zzet]

Summary

Found while reviewing #576. That PR made std::chrono::duration_cast(x) and boost::asio::post(ex) emit call edges at any qualification depth — but in a typical translation unit those calls sit in out-of-line member bodies, and those definitions extract as nothing at all.

void ns::Cls::run() {} declares itself with a qualified_identifier, which no function_definition pattern in qCppAll admitted (every one required declarator: (identifier)). No method node was emitted, and every call in the body went with it — a deferred call needs an enclosing function range to attach to. Probed against main before this change, a .cpp whose class lives in a header extracts only the file node and its imports edge:

#include "cls.h"

void Cls::depth2() { boost::asio::post(ex); }     // no node, no call edge
void ns::Cls::depth3() { std::chrono::duration_cast<int>(v); }   // same

Changes

• Each function_definition pattern now admits [(identifier) (qualified_identifier)] in the declarator slot.
• emitOutOfLineMember reads the qualifier structurally and lets the trailing segment decide the shape:
  • type owner → a method keyed on the owner (demo.cpp::Cls.run), member_of the class when this file declares it. Keying on the owner is what keeps void A::run() and void B::run() in one file from colliding on a single ID and dropping the second.
  • all-namespace qualifier → a free function carrying the qualifier as scope_ns, since void ns::helper() {} is not a member. A class/struct emitted from this file is proof of a type; otherwise the same Capitalized-name heuristic isCapitalizedCppType already uses decides.
  • Destructors, operators, pointer/reference returns, and out-of-line template members (template <typename T> void Holder<T>::put(T)) reach the same walk.
• Folds cppQualifiedCallName (added by fix(cpp): emit nested qualified call edges #576) and lastIdentifier into that single walk — a qualified callee and a qualified declarator are the same shape. lastIdentifier scanned direct children only, so once a name nested it returned the first segment rather than the last: ns::Cls::bar gave ns. One consequence of the shared walk is that a qualified operator call (ns::operator+(a, b)) now emits an edge instead of being dropped; covered by a test.

Testing

• go test ./internal/parser/languages -run Cpp -count=1 — all pass, including 7 new cases (depth 2/3/4 members, same-name members in one file, namespace-qualified free function, local-class member_of, destructor/operator/template member, qualified operator call, and a regression case pinning free functions and inline methods unchanged).
• go test -race ./internal/parser/languages -count=1
• go test ./internal/parser/... ./internal/resolver/... ./internal/indexer/... ./internal/semantic/lsp/... ./internal/search/rerank/... -count=1 — the packages carrying C++ fixtures outside the extractor.
• go build ./..., go vet ./internal/parser/languages, golangci-lint run ./internal/parser/languages/... (0 issues), git diff --check.