fix(kagi-aggregator): pass env vars to cron jobs

Cron runs in a separate environment that doesn't inherit the container's
environment variables. This caused the COVES_API_KEY to be unavailable
when the cron job executed, resulting in failed runs.

Fix:
- Export COVES_* and PATH to /etc/environment at container startup
- Source /etc/environment in crontab before running the aggregator

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[e-mail]>

aggregators/kagi-news/crontab

···
 # Run Kagi News aggregator daily at 1 PM UTC (after Kagi updates around noon)
-0 13 * * * cd /app && /usr/local/bin/python -m src.main >> /var/log/cron.log 2>&1
+# Source environment variables exported by docker-entrypoint.sh
+0 13 * * * . /etc/environment; cd /app && /usr/local/bin/python -m src.main >> /var/log/cron.log 2>&1
 
 # Blank line required at end of crontab
 

aggregators/kagi-news/docker-entrypoint.sh

···
 echo "API Key prefix: ${COVES_API_KEY:0:12}..."
 echo "Cron schedule loaded from /etc/cron.d/kagi-aggregator"
 
+# Export environment variables for cron
+# Cron runs in a separate environment and doesn't inherit container env vars
+echo "Exporting environment variables for cron..."
+printenv | grep -E '^(COVES_|PATH=)' > /etc/environment
+
 # Start cron in the background
 echo "Starting cron daemon..."
 cron