feat: HST/ACS reduction pipeline (phase 1)

[Jammy2211]

Implements the HST/ACS reduction pipeline designed under #1 and planned on #2 (autonomous run, --auto supervised; parked at ship sign-off per the autonomy contract).

What this adds

Production autoreduce package (spike → modules), all behind the ACS/WFC instrument adapter:

• target.py — declarative TargetSpec (YAML-loadable): coords, filter, proposal filter, cutout/PSF shapes, and the user-facing drizzle dials (final_pixfrac default 0.8, final_kernel square, final_scale 0.05″).
• instruments/ — adapter registry; acs_wfc carries native scale, _flc products, jref + CRDS subpath, default drizzle kwargs, saturation.
• acquire/ — MAST query with HAP-skycell hygiene + proposal/visit filtering; FLC download; CRDS bestrefs sync (skipped when cached + references present, so offline re-runs work); size-capped transient ExposureCache with provenance manifest (loud on spike-era schemas), per-target eviction sparing shared references.
• align/ — a-priori WCS provenance recording; TweakReg behind a trigger.
• drizzle/ — AstroDrizzle wrapper: cps/IVM/north-up, single-exposure branch (SLACS-V caveat), WHT RMS/median uniformity diagnostic, Casertano R recorded; lowercase-relative output root (drizzlepac lowercases paths — case-sensitive FS fix).
• noise/ — σ = R·√(max(sci,0)/t_exp + 1/W); NaN on bad weights, hard failure if any land inside the packaged cutout.
• psf/ — tier-1 ePSF: star cuts (point-like, unsaturated, uncrowded, edge-safe) + EPSFBuilder; 21×21 + 61×61 kernels; InsufficientStarsError hard stop with tier-2 as an explicit unimplemented interface (no silent degradation).
• package/ — WCS/units/EXPTIME-intact cutout headers + reduction.json (full per-stage provenance incl. software versions).
• pipeline.py — the orchestrator: acquire → align → drizzle → noise → psf → package → evict.

API Changes

New public API (nothing downstream consumes it yet): autoreduce.TargetSpec, autoreduce.reduce_target, autoreduce.instruments.{get,register,InstrumentAdapter}, plus stage modules. No changes to any other PyAuto* repo; autoreduce imports none of them.

Scripts Changed

• New scripts/reduce_slacs0008.py — integration/acceptance: production reduction of slacs0008-0004 + sub-pixel-registered parity vs the legacy dataset.
• prototypes/slacs_f814w_spike.py — Casertano fine-grid branch corrected ((p/s) → (s/p); spike results unaffected, it ran s=1).

Gate legs (supervised — parked at sign-off)

1. Tests: 53/53 pass (numpy/astropy-only; no network/drizzlepac in unit suite). Downstream suites n/a — no repo depends on autoreduce.
2. Smoke: n/a — no workspace script surface consumes autoreduce yet (stated per contract).
3. Review: review ran at high effort (8 angles, 3 finder passes + verification). FINDINGS → resolved in-branch: CRDS env now deterministically overrides inherited vars; CRDS subpath moved into the adapter (altitude); ePSF minimum-star contract re-checked post-extraction and edge margin raised to 36; manifest schema mismatches fail loudly; cached re-runs skip the network bestrefs sync; HDUList context-managed; provenance units label sourced from drizzle kwargs; hand-rolled sigma-clip replaced with astropy's. Deliberate non-fixes: tier-2 hard stop and mode="strict" cutouts are the no-silent-guards rule, not bugs. Deferred (noted, low stakes): O(N²) crowding rejection (fine at current N), crude FWHM diagnostic.
4. Heart: YELLOW — reasons: workspace validation failing (5), 58 stale parked scripts, autolens_assistant version skew, install verification not run, 63 script timing regressions, 9-day-old Mind PR. All pre-existing organism state, none related to this repo; maintainer acknowledged this exact reason set at sign-off (issue feat: HST/ACS reduction pipeline (phase 1) #2), authorizing PR-open.

Validation checklist

• 53 unit tests green on final state
• End-to-end integration on slacs0008-0004 (cached re-run after review fixes)
• Parity vs legacy dataset: data ratio 0.941, noise ratio 0.925 ≈ data ratio (noise recipe confirmed; R=1.364 applied), WHT uniformity 0.089, tier-1 ePSF from 31 stars
• Residual ~6% global flux scale vs legacy — accepted as documented difference (maintainer decision on feat: HST/ACS reduction pipeline (phase 1) #2); PyAutoMind research prompt filed to chase it if needed
• Comparative PyAutoLens fits + 2nd/3rd lens parity — deferred to a follow-up prompt (maintainer decision on feat: HST/ACS reduction pipeline (phase 1) #2)

🤖 Generated with Claude Code

https://claude.ai/code/session_01WNhuuvZLgZjHvWBGdhUst3

Closes #2 discussion at ship; merge remains a human act.