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/model/candidates.py

@@ -20,6 +20,8 @@ from dataclasses import dataclass, field
 from pathlib import Path
 from typing import TYPE_CHECKING, Literal
 
+from ..source import canonical_language
+
 if TYPE_CHECKING:
     from .taxonomy import FamilyTaxonomy
 
@@ -46,7 +48,6 @@ FAMILY_SHAPE: dict[str, tuple[CandidateKind, ...]] = {
 # The p90 of the measured distribution is 22 sites per labeled function, so two batches cover all but the tail.
 MAX_CANDIDATES_PER_CALL = 12
 _MAX_TEXT = 400
-_LANGUAGE = {"python": "python", "javascript": "javascript", "typescript": "typescript", "c_cpp": "c", "java": "java"}
 
 
 @dataclass(frozen=True)
@@ -233,7 +234,7 @@ def _line_text(lines: Sequence[str], line: int) -> str:
 def _language_of(path: str) -> str:
     from ..preprocess import detect_language
 
-    return _LANGUAGE.get(detect_language(Path(path)), detect_language(Path(path)))
+    return canonical_language(detect_language(Path(path)))
 
 
 @dataclass(frozen=True)