fix(makefile): add init-landing-seeds target for SQLMesh staging seed files

data/ is gitignored so seed files are not tracked. The recheck glob in
stg_playtomic_availability requires at least one matching file or DuckDB
throws IOException. Run 'make init-landing-seeds' after a fresh clone.

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

Makefile

@@ -5,6 +5,23 @@ bin/tailwindcss:
 	curl -sLo bin/tailwindcss https://github.com/tailwindlabs/tailwindcss/releases/latest/download/tailwindcss-linux-x64
 	chmod +x bin/tailwindcss
 
+# Create seed files for SQLMesh staging models that require at least one landing file.
+# Run once after a fresh clone (data/ is gitignored so seeds are not in git).
+init-landing-seeds:
+	@python3 -c "
+import gzip, json, os, pathlib
+seed = {'date':'1970-01-01','captured_at_utc':'1970-01-01T00:00:00Z','venue_count':0,'venues_errored':0,'venues':[]}
+morning = pathlib.Path('data/landing/playtomic/1970/01/availability_1970-01-01.json.gz')
+recheck = pathlib.Path('data/landing/playtomic/1970/01/availability_1970-01-01_recheck_00.json.gz')
+morning.parent.mkdir(parents=True, exist_ok=True)
+for p in [morning, recheck]:
+    if not p.exists():
+        with gzip.open(p, 'wt') as f: json.dump(seed, f)
+        print('created', p)
+    else:
+        print('exists ', p)
+"
+
 css-build: bin/tailwindcss
 	$(TAILWIND) -i web/src/padelnomics/static/css/input.css -o web/src/padelnomics/static/css/output.css --minify