feat: restructure extraction to one file per source

Split monolithic execute.py into per-source modules with separate CLI
entry points. Each extractor now uses the framework from utils.py:
- SQLite state tracking (start_run / end_run per extractor)
- Proper logging (replace print() with logger)
- Atomic gzip writes (write_gzip_atomic)
- Connection pooling (niquests.Session)
- Bounded pagination (MAX_PAGES_PER_BBOX = 500)

New entry points:
  extract              — run all 4 extractors sequentially
  extract-overpass     — OSM padel courts
  extract-eurostat     — city demographics (etag dedup)
  extract-playtomic-tenants      — venue listings
  extract-playtomic-availability — booking slots + pricing (NEW)

The availability extractor reads tenant IDs from the latest tenants.json.gz,
queries next-day slots for each venue, and stores daily consolidated snapshots.
Supports resumability via cursor and retry with backoff.

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

extract/padelnomics_extract/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "padelnomics_extract"
-version = "0.1.0"
+version = "0.2.0"
 description = "Data extraction pipelines for padelnomics"
 requires-python = ">=3.11"
 dependencies = [
@@ -9,7 +9,11 @@ dependencies = [
 ]
 
 [project.scripts]
-extract = "padelnomics_extract.execute:extract_dataset"
+extract = "padelnomics_extract.all:main"
+extract-overpass = "padelnomics_extract.overpass:main"
+extract-eurostat = "padelnomics_extract.eurostat:main"
+extract-playtomic-tenants = "padelnomics_extract.playtomic_tenants:main"
+extract-playtomic-availability = "padelnomics_extract.playtomic_availability:main"
 
 [build-system]
 requires = ["hatchling"]