Compress the compatibility page from narrative prose to a uniform
grammar — numbered rules with bold-lead invariants, Limitations, Checks
and Procedures, each carrying evidence pointers into the dsh source
tree — staged by lifecycle: supported set, admission, fold, metering
parity, client surface, projection cache, packaging, verification.
Drop what code, tests or git history already carry: the per-bump
stateVersion narratives, the V4 shape table, per-route architecture
stories and retired-version deltas. AGENTS.md gains the conciseness
mandate for the page: less is always better.