Fix first-run blockers: MOVIES_DIR path, CAM_NAME, .env for Python, eval safety

daily_sunrise_video.sh: use \$MOVIES_DIR instead of \$BASE_DIR/movies so the
override in sky-cam.conf is respected when videos live on a separate drive.

capture.sh: default camera name falls back to \$SUNRISE_CAM (not the
undefined \$CAM_NAME) when no argument is passed.

sunrise2mm.py: also loads .env after sky-cam.conf so Mattermost credentials
moved to .env are actually visible to the upload script.

sunrise.py: raise a clear error message when LATITUDE/LONGITUDE/TIMEZONE
are missing from sky-cam.conf instead of an opaque KeyError.

4-seasons.sh, montage-mvt.sh: capture season_info.py output before eval so
a Python failure exits cleanly with a diagnostic message rather than
silently continuing with undefined variables.

bootstrap.sh: add system package install step (ffmpeg bc fonts-dejavu) and
show the .env setup step after install.sh generates .env.example.

README.md: correct Python package names and add fonts-dejavu dependency.

https://claude.ai/code/session_01C4jbd3waXG3eKZYbGUjLUQ

daily_sunrise_video.sh

@@ -24,7 +24,7 @@ current_date=$(date +%Y-%m-%d)
 output_date=$(date +%Y-%m)
 
 image_dir="$BASE_DIR/$CAM_NAME/$current_date"
-output_dir="$BASE_DIR/movies/$CAM_NAME/$output_date/sunrise-only"
+output_dir="$MOVIES_DIR/$CAM_NAME/$output_date/sunrise-only"
 mkdir -p "$output_dir"
 
 # ── Sunrise time ──────────────────────────────────────────────────────────────