fix(c-parser): deterministic include resolution + call-graph precision/recall

[gadievron]

c/call_graph_builder built include_map by basename/suffix match into an unordered
set, then resolved calls by first-of-set, and the regex fallback / call-name
extraction emitted several classes of false or missing edges. This repairs both
the include-resolution determinism and the resolver precision/recall in one change
to the C call-graph builder.

Deterministic, path-anchored include resolution:
Two compounding faults:
(1) bare endswith(inc) over-matched any tail (include "x.h" -> "src/prefix-x.h")
and every same-basename header repo-wide;
(2) first-match over the unordered set made the resolved callee depend on set
iteration order -> flipped across PYTHONHASHSEED.
Fix: require a path-component boundary (other_file == inc or endswith('/'+inc))
and iterate sorted(included_files) for a stable lexicographic tiebreak.

Resolver precision/recall:

• _extract_calls_regex scanned raw code, so call-shaped tokens inside // or /* */
  comments or "..." / '...' literals became phantom edges. Blank out comments and
  string/char literals (length/newline preserving) before the regex scan.

• obj->cb() (field_expression callee) was reduced to the bare field name and
  resolved against the global free-function index, wiring the member/function-pointer
  call to an unrelated free function. _extract_call_name now declines (returns None)
  for field_expression -> no false edge. The resolver has no receiver-type model, so
  name-only binding of a member call is wrong.

• A function passed by name as a callback argument (qsort(..., my_cmp),
  pthread_create(..., worker, ...), signal(2, &handler)) produced no edge because
  only the call's 'function' child was inspected. Scan the 'arguments' child for
  bare-identifier / &name args that resolve to a known function and emit the
  caller->callback edge. Non-function identifiers do not resolve, so data args
  create no edge.

• The unique-name (and included-header and prototype) fallbacks returned a static
  (file-local) function in another translation unit, violating C internal linkage.
  New _is_visible_from guard requires a cross-file candidate to be non-static;
  same-file definitions stay visible. is_static and file_path are already in the
  extractor output.

Out of scope (no code change): recording unresolved/ambiguous direct-name calls,
field-pointer derefs, and tbli subscript-expression callees into an
indirect_calls store — that sink does not exist in any of the parsers (0 producers /
0 consumers); building it end-to-end is out of scope. Dropping these calls emits no
false edge (the safe outcome).

Tests (hermetic): tests/parsers/c/test_c_include_map_determinism.py (2; over-match

• {F_bar,F_foo} flip across PYTHONHASHSEED 0..9) and
  tests/parsers/c/test_c_call_resolution_precision.py (9). Full suite: 187 passed,
  63 skipped (no regression). ruff check -> All checks passed.

Scope: C-only (grep -c 'include_map[.*] = set()': c=1, python/php/ruby/zig=0).

Co-Authored-By: Claude Opus 4.7 (1M context) noreply@anthropic.com