feat: copier update v0.9.0 — extraction docs, state tracking, architecture guides

Sync template from 29ac25b → v0.9.0 (29 template commits). Due to
template's _subdirectory migration, new files were manually rendered
rather than auto-merged by copier.

New files:
- .claude/CLAUDE.md + coding_philosophy.md (agent instructions)
- extract utils.py: SQLite state tracking for extraction runs
- extract/transform READMEs: architecture & pattern documentation
- infra/supervisor: systemd service + orchestration script
- Per-layer model READMEs (raw, staging, foundation, serving)

Also fixes copier-answers.yml (adds 4 feature toggles, removes stale
payment_provider key) and scopes CLAUDE.md gitignore to root only.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

infra/supervisor/padelnomics-supervisor.service

@@ -0,0 +1,24 @@
+[Unit]
+Description=Padelnomics Supervisor — Pipeline Orchestration
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+User=root
+WorkingDirectory=/opt/padelnomics
+ExecStart=/opt/padelnomics/infra/supervisor/supervisor.sh
+Restart=always
+RestartSec=10
+EnvironmentFile=/opt/padelnomics/.env
+Environment=LANDING_DIR=/data/padelnomics/landing
+Environment=DUCKDB_PATH=/data/padelnomics/lakehouse.duckdb
+
+LimitNOFILE=65536
+
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=padelnomics-supervisor
+
+[Install]
+WantedBy=multi-user.target