feat(scanners): model/effort routing becomes a lever, not a 25th dimension (C4)

New GAP finding CA-GAP-028: authored subagents exist and not one of them names
`model:` or `effort:`, so every delegated task runs on the main conversation's
model (`model` defaults to `inherit`). Cites BP-MODEL-001/002, landed in C1.
`whats-active` and `manifest` now carry `model`/`effort` per agent.

Shipped as a conditional LEVER rather than a 25th dimension, and the choice was
made by measurement: as a t3 dimension the agent-less marketplace-medium fixture
would count it vacuously-present, moving the denominators 41->42 and utilization
44->45 — which flips `segment` "Developing"->"Competent" in the frozen v5.0.0
posture baseline, a field strip-retired-gap.mjs does not mask. A lever never
enters those denominators. The general rule is now an invariant in CLAUDE.md.

One check across both axes, not one per axis: it fires only when neither is used
anywhere, so a deliberate everything-on-one-model policy stays silent. Cost is
recall, chosen for precision.

Found by dogfooding, fixed red-first: `model: inherit` is the documented default
spelled out, so it must not count as routing — otherwise a config opts out of the
opportunity without changing anything real.

Two pre-existing defects surfaced and closed on the way:
- The humanizer guard asserted TRANSLATIONS.GAP.static EQUALS the dimension
  titles, which forbade humanizing any lever — all three existing levers fell
  through to the generic "feature opportunity" default, wrong for a budget lever.
  Guard now requires coverage of every emittable title, seen red against those
  three before the entries were written.
- Two hand-written copies of the lever list (finding-codes guard, humanizer
  guard) merged into one exported LEVERS registry carrying code AND title.
- suppression-validation pinned CA-GAP-028 as an unoccupied number; C4 claimed
  it. Fixed structurally with a derived first-free id, not by picking a new
  literal — same class as #60's "bump this again".

Suite 1596/0. Frozen v5.0.0 snapshots untouched.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq3nye21RVYk4pZLeT8pGz

docs/scanner-internals.md

@@ -221,6 +221,46 @@ returns ≥1 chatty hook — surfaces the documented **filter-before-Claude-read
 grep ERROR and return only matches instead of a 10,000-line log). No chatty hook → silent (opportunity,
 not noise — same contract as the cliOverMcp / bundledSkills levers).
 
+### feature-gap — agent model/effort routing lever (v5.14 C4, `CA-GAP-028`)
+
+`agentModelRoutingLeverFinding` fires only when the target has **authored** subagents (the same
+`isAuthoredConfig` set the presence checks use, so plugin-bundled and fixture agents cannot make a
+machine look routed — M-BUG-13) and **not one of them** names `model:` or `effort:`. Cites
+`BP-MODEL-001` (a subagent's `model` defaults to `inherit`, so omitting it is a choice to pay the
+session's rate) and `BP-MODEL-002` (effort is a separate axis with its own frontmatter field).
+
+**Why a lever and not a 25th dimension — decided by measurement, not taste.** A dimension is always
+evaluated, so "no agents at all" would have to read as *present*, and present weight feeds the
+utilization score. Measured on `tests/fixtures/marketplace-medium` (hermetic HOME) before the change:
+`utilization.score` 44, `segment` "Developing", where the "Competent" boundary is 45. As a t3
+dimension the denominators move 41→42 and the vacuous present pushes 18/41→19/42 = **45** — flipping
+`segment` in the frozen `v5.0.0/posture.json`, which `strip-retired-gap.mjs` does **not** mask (it
+drops only `utilization.score`/`overhang` and `feature_coverage.score`). A lever leaves every
+denominator alone and cannot move a score it never enters. The general rule now lives in CLAUDE.md
+(*GAP dimensions vs. levers*).
+
+**One check across both axes, not one per axis.** It fires only when *neither* axis is used anywhere,
+so a deliberate everything-on-one-model policy stays silent. The cost is recall: a config that pins
+`model:` everywhere but never `effort:` gets no nudge. That is the v1 boundary, chosen for precision.
+
+**`model: inherit` is not routing** — found by dogfooding, where installed agents write it out
+explicitly. `inherit` is the documented default, so spelling it out changes nothing about what the
+agent costs; counting it as a pin would let a config opt out of the opportunity without changing
+anything real. Effort has no documented sentinel of this kind, so it has no counterpart rule.
+
+**Two silences that must not be conflated.** "No authored agents" (owned by dimension `t2_6`,
+*No custom subagents*) and "the only agents on disk are plugin-bundled" produce the same quiet
+output for different reasons. `tests/scanners/gap-agent-model-routing.test.mjs` P5 pins the second
+one specifically — it asserts the agent file *was* discovered before asserting silence, so the arm
+cannot pass for P4's reason.
+
+**Humanizer coverage is now a blanket invariant.** The old guard asserted `TRANSLATIONS.GAP.static`
+keys *equal* `GAP_CHECKS` titles, which forbade humanizing any lever — so all three existing levers
+fell through to the generic GAP `_default` ("You have a feature opportunity worth a look"), wrong for
+a budget lever. The guard now requires a static entry for **every title GAP can emit** (dimensions ∪
+levers), and it was seen red against those three before the four entries were written. `TITLE_TO_ID`
+keeps strict equality with `GAP_CHECKS`: levers are not dimensions and must stay out of scoring.
+
 ### cache-prefix-scanner — @import extension (v5.10 B6)
 
 CPS originally scanned only the files discovery classifies as `claude-md`. But a CLAUDE.md can pull