Cleanup/remove dead files empty folders

.gitignore

@@ -23,60 +23,31 @@ venv/
 *.code-workspace
 .DS_Store
 
-# Archived working notes
-**/.archive/
-**/_archive/
-
-# Database: local-dev scripts and secrets
-database/secrets/
-database/setup_db_connection.sh
-database/setup_developer_session.sql
-database/scripts/*.sh
-
-# Environment-specific SQL variants
-database/scripts/sql/**/*_local.sql
-database/scripts/sql/**/*_cloud9.sql
-
-# ETL: development staging and reference
+# Generated SQL. load_all_tier_results.py writes etl/tier_data/output/all_tiers.sql
+# here, then psql-ed into the database. Regenerated on demand, so not tracked.
 etl/**/output/
+
+# Audit files generated by etl/statistics/run_all.py, lib/runner.py,
+# scan_dupes.py, and the ingestion tools (etl/ingestion/lib/commands.py). They
+# are timestamped and they pile up.
 etl/**/audit_reports/
-etl/statistics/charts/
-etl/reference/
+
+# PDF charts generated by etl/statistics/visualize_percentile_bands.py.
 etl/verification/*.pdf
 
 # Generated manifest, regenerated by load_all_tier_results.py
 etl/tier_data/staging/tier_upload_manifest.csv
 
-# audits/
+# audits/: 
+# whitelist only the committed monthly snapshot dirs.
+#
 /audits/*
-!/audits/README.md
 !/audits/monthly_*/
 !/audits/monthly_*/**
-# Tarballs duplicate the unzipped monthly directories.
-/audits/*.tar.gz
-/audits/monthly_*/*.tar.gz
-
-# AWS cost dumps (local-only)
-costs/
 
-# aws lambda invoke output file (per lambda READMEs)
+# When running `aws lambda invoke ... response.json` (i.e. when manually triggering a lambda), 
+# the result would write here. This is the filename used in the lambda READMEs.
 **/response.json
 
-# Default-ignore everything under data/, then re-allow the specific subdirs
-# that should be tracked.
-/data/*
-!/data/README.md
-!/data/raw/
-/data/raw/*
-!/data/raw/csv_from_CalSim_report_pdf/
-!/data/raw/csv_from_CalSim_report_pdf/**
-!/data/raw/pdf_tables_from_CalSim_report/
-!/data/raw/pdf_tables_from_CalSim_report/**
-!/data/reference/
-/data/reference/*
-!/data/reference/cws/
-!/data/reference/cws/**
-!/data/reference/CS3_NetworkSchematic-Hongbing.pdf
-
 # LibreOffice lock files
 **/.~lock.*