context: a question naming a file outside the index is answered from unrelated word matches, without saying the file was not indexed #1571

Symptom

When a context question names a file that exists in the repository but is outside the index (a language the index skipped, or one it does not support), the answer is seeded from unrelated matches on the question's generic words. It never says that the named file exists and was not indexed.

$ axiomcode context "where is the souffle rule file callee-resolution.dl loaded by run-souffle.sh"
entry points (6, best match per term — the graph's own words, not a guess):
    NodeScopeRule                                   parser/src/parsers/java/extractors  matches 'rule'
    GradleFileExtractor.processDeclarationFromMeth  parser/src/parsers/gradle/extracto  matches 'file'
    JsCallResolutionOutcome                         parser/src/enums/javascript/call-s  matches 'callee'
    TsLocalResolver.run                             ...                                 matches 'resolution'
    Loaded                                          parser/src/test-data/...            matches 'loaded'

Both callee-resolution.dl and run-souffle.sh exist in the tree (there are 30+ .dl files). A question about Python hook scripts in a TypeScript-only graph gave the same kind of answer: entry points in .d.ts and Java-extractor files, and no mention that the matching .py files are outside the graph. This came up in five agent sessions, over CLI and MCP.

Expected

When a task word matches a file name on disk that the index does not cover, the answer says so first: the file, its language, and that the graph cannot answer about it. That lets the agent go straight to reading the file. #1470 covers the same gap for changed, test-impact and context --in; this issue covers a context question that names such a file without --in.