refactor(p1): one source-facts module owns function ranges, callers, declaration tables and language aliases

src/openultrasast/source.py replaces the copies in semantic/functions.py,
plane/tasks/repo_facts.py, learn/features.py, learn/excerpt.py and
plane/tasks/verify.py. Two engines share one sentinel (<module>), one
DECLARATION/KEYWORDS/RESERVED set and one alias map: the parser engine
(ranges, enclosing, bounds, call_sites, callers_of, facts_for) for the
scorer, the overlay and the hunter's annotations; the line-pattern engine
(declared_functions, enclosing_at, function_span, function_bounds, the brace
matcher) that labels, features, roles, excerpts and plane facts were built
on. learn no longer imports plane.tasks. Frozen records that store the old
sentinel are mapped on read (module_function).

Gate: labels rebuilt before and after are identical, 7,921 rows, after
sentinel normalisation (benchmarks/measurements/2026-10-13-source-module-
label-diff/record.json). 490 targeted tests pass; 3,312 collect. Net: 657
lines deleted, 212 added. benchmarks/unseen keeps <global> for its own
frozen manifests.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

src/openultrasast/hunter_tools.py

@@ -6,6 +6,7 @@ from collections.abc import Iterator
 from pathlib import Path
 
 from .preprocess import enumerate_source_files
+from .source import callers_of, product_files
 
 
 class PathEscapesRepo(ValueError):
@@ -81,15 +82,13 @@ def grep_repo(root: Path, pattern: str, *, max_matches: int) -> list[dict[str, o
 
 
 def find_refs(root: Path, symbol: str) -> list[dict[str, object]]:
-    resolved_root = root.resolve()
-    refs: list[dict[str, object]] = []
-    if symbol:
-        compiled = re.compile(rf"\b{re.escape(symbol)}\b")
-        for relative, lines in _source_lines(resolved_root):
-            for line_no, line in enumerate(lines, start=1):
-                if compiled.search(line):
-                    refs.append({"path": relative, "name": symbol, "line": line_no, "text": line[:_LINE_CHARS], "source": "text"})
-    return refs
+    if not symbol:
+        return []
+    lines = dict(_source_lines(root))
+    return [
+        {"path": path, "name": symbol, "line": line, "text": lines[path][line - 1][:_LINE_CHARS], "source": "text"}
+        for path, line in callers_of(root, symbol, files=product_files(root))
+    ]
 
 
 def _iter_clamped_source_files(root: Path) -> Iterator[tuple[str, Path]]: