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

bootstrap.sh

@@ -20,7 +20,9 @@ mv "sky-cam-$BRANCH" "$TARGET"
 
 echo ""
 echo "Done. Next steps:"
-echo "  1. pip3 install suntime pytz requests"
+echo "  1. Install system packages (if not already present):"
+echo "       sudo apt install ffmpeg bc fonts-dejavu"
+echo "       pip3 install suntime pytz requests"
 echo ""
 echo "  2. Edit $TARGET/sky-cam.conf"
 echo "     — SCRIPT_DIR   full path to the directory you'll run scripts from"
@@ -29,6 +31,8 @@ echo "     — MUSIC_DIR    path to your Vivaldi Four Seasons audio files"
 echo "     — CAMERAS      list of camera names, e.g. (sunrise)"
 echo "     — SUNRISE_CAM  which camera faces east (gets the sunrise video job)"
 echo "     — LATITUDE / LONGITUDE / TIMEZONE   your location"
-echo "     — Mattermost credentials (mattermost_url, access_token, channel_id)"
 echo ""
 echo "  3. cd $TARGET && ./install.sh"
+echo "     This generates .env.example — copy it to .env and add credentials:"
+echo "       cp $TARGET/.env.example $TARGET/.env"
+echo "       \$EDITOR $TARGET/.env"