Pay the ranker's own debt: four ccg queries whose answer was retrieved but left off the page #95

Parent

#51

What to build

Four queries on ccg score nothing even though retrieval already handed the ranker the judged answer. They are the only entries in zeroScoreNotes a reordering can pay; every other zero died in retrieval, where no ranking change can reach it.

All four are question-shaped, judged at file granularity, and answered by the intent index rather than the name index. The first one's note records why the name index contributes nothing here: SanitizeFTS5 joins terms with a space and FTS5 reads a space as AND, so a six-word question needs all six words in one document. Ordering is left entirely to the intent scorer.

Make the intent scorer put these answers on the page of ten.

The constraint that makes this hard, stated first

The ranking rule applies to every query. Raising these four can lower the 73 that answer today. testdata/README.md states the rule this must satisfy: a change that moves a ranking number must hold or improve it on every corpus — ccg, gorm, cobra and context-diary. A gain on ccg paid for by a loss elsewhere is an overfit by definition.

The same file forbids the obvious shortcut: "Do not tune constants against these numbers. Every constant that would raise them — a score floor, a stopword list, a length penalty — is fitted to one codebase's vocabulary." A change that survives is a correctness fix or something the runtime recomputes per corpus, not a number picked because it moved these four.

If no such change is found, say so and close this as not-yet-payable rather than shipping a fitted constant. That is an acceptable outcome for this ticket.

Acceptance criteria

• At least one of the four queries puts its judged file on the page of ten. State which ones moved and which did not.
• make search-eval output is reported in full for all four corpora, next to main's output for the same command. No corpus regresses on Recall@10, top1, top3 or MRR.
• Any query that starts scoring has its zeroScoreNotes entry removed — the guard already fails on a note whose entry no longer scores zero, so this is forced, not optional.
• baseline.json regenerated by running the harness, never hand-edited.
• The change is stated in one sentence as a rule, not as a number: what the scorer was getting wrong about these questions. If that sentence needs a constant to be true, it is the shortcut the tuning rule forbids.
• CGO_ENABLED=1 go test -tags "fts5" ./... -count=1 green, and the same with TEST_POSTGRES_DSN set and REQUIRE_POSTGRES=1.

Out of scope

The five known gap entries retrieval never answered — mcp, what happens when a webhook arrives, where do search results get ranked, why does editing a function with many outgoing links rank as riskier, what decides whether generated documentation may delete an existing page. No reordering can pay those; the index or the tokenizer has to change first. Do not widen this ticket to chase them.

Blocked by

None — can start immediately.