Simplify moon phase: binary go/no-go, parallactic angle rotation, no atmosphere overlay

- moon_composite.py: remove _make_atmosphere_layer() and all atmosphere
  parameters from render_phase_closeup(); add when_utc parameter and apply
  parallactic angle rotation so the NASA disk is oriented to match east's sky

- moon_phase_monthly.py: change obs time default to 22:00 (aligns with NASA
  hourly renders); scan east frames in 22:00-23:00 window; binary go/no-go
  (quality >= MIN_QUALITY = post, no clear shot = skip entirely); remove
  _atmosphere_opacity_from_quality(), ATMOSPHERE_BLUR, CLOUDY_POST_ENABLED

- sky-cam.conf: update MOON_OBS_TIME_LOCAL to 22:00, remove
  MOON_OBS_WINDOW_MIN, remove the atmospheric overlay and cloudy fallback
  sections and their config variables

- test_moon_composite.py: single clean test — fetch NASA for 22:00 UTC on
  2026-04-29, verify east frame quality, render with parallactic angle; no
  procedural fallback

https://claude.ai/code/session_01HkTxpNSTWtViZzxbrbKytR

sky-cam.conf

@@ -492,20 +492,18 @@ MOON_TRACK_CRF=24                  # output mp4 CRF
 MOON_TRACK_RETENTION_DAYS=90       # delete tracker mp4s older than this; 0 = forever
 
 # Observation time ────────────────────────────────────────────────────────────
-# Local time used to select the east camera frame and the NASA Dial-a-Moon
-# render for each phase post.  The script looks at east frames within
-# ±MOON_OBS_WINDOW_MIN of this time on the night of the exact phase event,
-# picks the one closest to the target time, and uses it to:
-#   1. Determine atmospheric conditions (clear / hazy / overcast)
-#   2. Set the atmosphere overlay opacity on the NASA moon image
-#   3. Round to the nearest hour for the NASA API call
+# Local time that defines the observation window: MOON_OBS_TIME_LOCAL to
+# MOON_OBS_TIME_LOCAL+1h.  East frames in this window are checked for a clear
+# moon detection (quality >= MOON_MIN_QUALITY).  If any frame qualifies, the
+# NASA Dial-a-Moon image for MOON_OBS_TIME_LOCAL UTC is fetched and posted.
+# If no frame shows a clear moon, the month is skipped entirely.
 #
-# 22:30 works well for full moon and first quarter (both visible after dark).
-# For third quarter (rises after midnight), consider 02:30 or leave at 22:30
-# and accept that the moon may be below the horizon — the script will warn
-# and post a clean NASA render instead.
-MOON_OBS_TIME_LOCAL=22:30
-MOON_OBS_WINDOW_MIN=30              # ±minutes around obs time to check east frames
+# 22:00 aligns directly with NASA's hourly renders.  Full moon and third
+# quarter both rise after dark and are visible at this hour.  First quarter
+# is up only until ~midnight from a new-moon start, so it may not be visible
+# at 22:00 depending on the exact date — set MOON_FIRST_QUARTER_ENABLED=false
+# if first-quarter posts are consistently missed.
+MOON_OBS_TIME_LOCAL=22:00
 
 # Post delay ──────────────────────────────────────────────────────────────────
 # How many days after the exact phase to run the post.  The post delay gives
@@ -537,33 +535,6 @@ MOON_HEIGHT_PCT=0.92               # moon disk fills this fraction of frame heig
 MOON_DIALAMOON_TARGET_PX=2048      # cached PNG longest side; downsampled on save
 MOON_DIALAMOON_TIMEOUT_SEC=30
 
-# Atmospheric overlay ─────────────────────────────────────────────────────────
-# East's camera frame is scaled to output size, blurred, and composited OVER
-# the NASA moon disk.  This is physically correct: clouds sit between the
-# observer and the moon, so they occlude the disk rather than appear behind it.
-#
-# Opacity is derived from the moon detection quality in that frame:
-#   quality ≥ 0.85  →  0%  (clear sky — pure NASA render)
-#   quality   0.70  → 20%  (light haze)
-#   quality   0.55  → 40%  (notable cloud, moon still detected)
-#   quality < 0.55  → 40–65% (overcast fallback — see MOON_CLOUDY_POST_ENABLED)
-#   no detection    → 68%  (heavy overcast)
-#
-# blur radius: 0 = auto (output_width / 10); set in px to override.
-#MOON_ATMOSPHERE_BLUR=0
-#
-# Cloudy-month fallback ───────────────────────────────────────────────────────
-# If no frame in the collection window passes the quality + illumination
-# thresholds, the script normally skips posting that month.  With
-# MOON_CLOUDY_POST_ENABLED=true it instead finds the above-horizon frame
-# closest to the exact phase moment, applies a heavy atmospheric overlay
-# (opacity 0.45–0.68), and posts the month anyway — the moon shows as a faint
-# glow behind cloud rather than being absent entirely.
-#
-# This applies to all three phases: full, first-quarter, third-quarter.
-# Caption will read "cloud cover — YYYY-MM-DD — NASA SVS Dial-a-Moon".
-MOON_CLOUDY_POST_ENABLED=true
-
 # ── Mattermost — daily sunrise upload ─────────────────────────────────────────
 # mattermost_url, access_token, channel_id go in .env (see bottom of this file).