## Motivation
The full 16-slot run came back 139 passed, 5 failed. Four of the five were `coverage uneven across minors` on `resolute` and `alpine324` (both arches) — and they are not defects.
Those slots are built under R 4.5, so their 4.5 union carries ABI-risky packages that only exist as 4.5 builds. A 4.4 or 4.6 client cannot safely load them, which is the whole reason per-minor slots exist. Their absence from the 4.4 and 4.6 indexes is correct behaviour, and failing the run on it blocks four slots that regress nobody.
This is the same mistake as the source-fallback share, which was demoted to a note for the same reason.
## Change
Report uneven coverage; do not fail on it.
The two checks answer different questions and should not share an exit code:
- **`MAX_REGRESSIONS`** gates *enablement*: would routing serve a client source where the generic slot holds a binary of that client's own minor? Must be zero.
- **parity** gates the *claim*: can we advertise full coverage for ABI-sensitive packages? Informative, and currently no.
## Verification
`amd64/resolute` now passes with the shortfall printed as a note:
```
ok amd64/resolute R 4.6: no regression against the generic slot
note: amd64/resolute coverage uneven across minors (vs best 24748): R4.4:-345 R4.6:-352
passed: 8 failed: 0
```
`shellcheck` clean.
Reviewed-on: #180
pat-s
d38a4b5746