The full init -> commit -> push over mbedTLS HTTPS now runs on hardware
(verified device-side + via git ls-remote). Documents the three fixes that
got there -- 96 KB main stack, remove-then-rename p_rename, and the utimes
existence-gate that had silently dropped every ODB write -- plus the
shortcuts still standing (cert bypass, PAT-in-flash, SSH-vs-HTTPS remote).
bcb4ffa465