Wire-protocol robustness, cross-driver session smokes, and a 100%-honest gauge
Summary: Malformed BSON in command bodies now elicits a BadValue reply instead of dropping the connection, sessions and cluster-role bundles get cross-driver smokes (mongosh + Node + Go + Java), and the pymongo conformance dashboard catches up to the gauge it was always passing — a clean 100.0% (v0.3.0a78).
The wire layer is more forgiving where it should be and stricter where it must be. A request whose body BSON is malformed used to drop the connection mid-conversation; it now returns a structured BadValue reply and keeps the socket alive, matching what mongod does and letting drivers retry the operation cleanly. Session tracking and cluster role bundles (clusterMonitor, clusterAdmin, backup, restore) — both shipped in recent releases — gained cross-driver smoke coverage so the pymongo gauge no longer stands alone for those features: mongosh, the Go driver, the Node driver, and the Java driver all exercise the same call shapes against SecantusDB and assert the right answers.
hostInfo and whatsmyuri return real values (hostname, OS, CPU arch, RAM, real connection peer) instead of placeholders, and $dateToString handles the full set of mongod tokens including the %w (1-Sun … 7-Sat) numbering that diverges from POSIX. The pymongo conformance gauge sits at 100.0% — the previous 99.5% reading was a report-generator bug that miscounted pytest-subtests "subtests passed" lines as errors; every category was always green when run, the dashboard just said otherwise. The number on the page now matches reality.