feat: JWST/NIRCam via the COSMOS-Web ring, four bands (phase 3)

[Jammy2211]

Implements JWST/NIRCam support per #6, rebased onto main after PR #5 merged. Autonomous run (--auto supervised); shipped at PR-open on maintainer sign-off.

What this adds

• Backend dispatch (the altitude work): InstrumentAdapter.combine_backend routes stage 3 to astrodrizzle (HST) or jwst_image3 (calwebb_image3); CRDS server/env shape (observatory, crds_server_url, mast_obs_collection) is adapter-owned.
• instruments/nircam.py — nircam_sw/nircam_lw + filter→channel routing; recommended output scales 0.03″/0.06″ (COSMOS-Web convention).
• drizzle/jwst_combine.py — calwebb_image3 with the lensing dials mapped to resample; save_results=True, in_memory=False (image3 OOM'd this machine otherwise); _i2d normalized to standalone sci/wht/err so downstream stages stay backend-agnostic.
• noise/jwst_rms.py — read propagated ERR × Casertano R + blank-sky consistency check (the roadmap's "read, don't construct").
• acquire/footprint.py — detector-footprint filter (pixel-space containment, immune to RA-wrap/cos-dec box pitfalls): only exposures covering the target enter combination — on COSMOS-Web SW visits this discarded 52 of 64 exposures.
• Bad-pixel policy (noise/rms.py + package/cutout.py split): isolated dead/rejected pixels → masked-by-noise (1e8, the legacy convention), recorded in provenance; loud failure preserved for structured clusters, >0.5% of the cutout, or anything within 1.5″ of the lens.
• PSF options from the WL+AGN literature (docs/design/jwst.md): ShOpt/PSFEx/PIFF (COSMOS-Web WL) + Zhuang & Shen (AGN) ⇒ LW single ePSF adequate (~0.6% RMS spatial variation), SW/WL-grade needs spatially-varying PSFEx/ShOpt (tier-2 follow-up), STPSF an explicit flagged fallback only.

Four-band COSMOS-Web ring validation (vs the assistant demo products)

Acceptance bar per maintainer guidance: close + internally consistent, not reproduction — the demo descends from the bespoke COSMOS-Web team pipeline.

Band	n_exp (skipped)	sky/ERR closure	R	ePSF stars	data ratio	noise ratio
F115W (SW 0.03″)	12 (52)	1.075	1.525	56	1.385	1.476
F150W (SW 0.03″)	12 (52)	1.005	1.525	96	0.812	1.596
F277W (LW 0.06″)	8 (8)	0.956	1.538	302	1.021	0.576
F444W (LW 0.06″)	8 (8)	0.883	1.538	253	1.551	0.733

Internal closures pass everywhere (sky vs ERR floor within ~12%; ≤1 masked pixel/band; units MJy/sr recorded). Parity is order-unity in all bands with per-band scatter in both directions — consistent with the team pipeline's per-band bespoke steps, and inside the agreed bar. Cutout WHT uniformity 0.25–0.31 where measured (sparse COSMOS-Web dithers; reported per run).

API Changes

New adapters + adapter fields (all defaulted — HST adapters unchanged, verified by regression tests); autoreduce.acquire.footprint; noise.jwst_rms; noise.rms.mask_isolated_bad_pixels; package.cutout.make_cutout/write_fits. No other PyAuto* repo touched.

Scripts Changed

New scripts/reduce_cosmos_web_ring.py (four bands + parity). Design docs: jwst.md (deltas, PSF tiering, parity interpretation), roadmap tick.

Environment note

~/venv/PyAuto gained jwst 2.0.1 (1.14 wheels crash under numpy 2) and scipy moved 1.14.0 → 1.17.1 (inside autoarray's declared cap); astropy/numpy/jax unchanged and autolens verified working.

Gate legs (supervised — parked at sign-off)

1. Tests: 83/83 (62 phase-1/2 regression + 21 JWST/footprint/policy). Downstream suites n/a (no dependents).
2. Smoke: n/a — no workspace surface consumes autoreduce (stated per contract).
3. Review: finder+verify on the phase-3 delta → 6 findings: 5 fixed (pixel-space footprint containment replacing the RA-wrap/cos-dec box; jwst path decoupled from EXPTIME; structured-defect loudness added to the masking policy; masked-pixel bleed excluded from parity stats; chdir path resolve), 1 noted (footprint's real-WCS assumption — empirically exercised by all four bands). Two review concerns verified not-bugs (center_xy axes; WHT normalization in the uniformity statistic).
4. Heart: YELLOW — same pre-existing organism reason set as PRs feat: HST/ACS reduction pipeline (phase 1) #3/feat: WFC3 (UVIS + IR) reduction support (phase 2) #5; none related to this repo. Maintainer acknowledged at sign-off (issue feat: JWST/NIRCam via the COSMOS-Web ring, four bands (phase 3) #6), authorizing PR-open.

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