# GAL-FINGERPRINT-I Chamber v0.2.2 — Gate C engineering revision report

## Implemented scope

This revision implements the accepted next engineering action after the Gate B pass:

1. controller/runtime provenance is corrected to `0.2.2` for all new outputs;
2. the historical Gate B distinction is recorded as successful runtime `0.1.3` versus legacy exported controller label `0.1.0`;
3. deterministic n=10 thinning is separated from random stratified thinning;
4. only the four primary Gate C branches are executable;
5. registered Gate C retrieval analysis is implemented.

## Authorized branch counts

```
LEAVE_ONE_RADIUS_OUT                 782
THINNING_N10_DETERMINISTIC           121
COVERAGE                             242
ML_SENSITIVITY                       302
TOTAL                               1447
```

## Locked branches

```
THINNING_N10_RANDOM                  363
NULL_GAP_ORDER                       605
NULL_UNIFORM_RANGE                   605
REPEAT                               Gate B complete; no further repeats authorized
```

## Analysis products

The Gate C analyzer uses the coordinate-wise mean of R1–R5 as the reference fingerprint. It evaluates the registered full-curve `rho_rms` metric, the frozen combined and PCA sensitivity metrics, ordinary-geometry-matched impostors, source ranks, top-1/top-5 retrieval, within/between ratios, margins, and top-five neighbour Jaccard stability.

## Provenance behavior

New direct exports record:

```
controller_version          0.2.2
runtime_package_version     0.2.2
measurement_kernel          STRUC-I
measurement_kernel_version  1.0.4
gate                        GATE_C
```

The original R2–R5 files are never rewritten.

## Engineering verification

- frozen primary sample and 121 ladder hashes validated;
- genuine R2–R5 run-package result hashes validated against the Gate B record;
- exact branch counts validated;
- deterministic/random thinning split validated;
- STRUC-I core equivalence retained for 15 canonical functions;
- browser-to-Python immutable run binding retained;
- short-path atomic checkpoint probe passed;
- a disposable real-engine Gate C checkpoint was accepted (`1/121`);
- a disposable 1,447-profile end-to-end Gate C analysis fixture completed and produced four branch passes, then all fixture outputs were deleted.

No Gate C scientific measurements or verdicts are included in the chamber package.

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## v0.3 project interpretation

This document contributes to the galaxy structural-fingerprint programme. Numerical, technical, protocol, or provenance content above is preserved. The canonical interpretation is that the fingerprints are reproducible, organized, and galaxy-specific; sampling, coverage, and baryonic-preparation dependence describe the transformation of fingerprint expression and do not erase the structural finding.

