* Throttle async session-activity writes to once per token per minute
* Add singleflight to session lookups, keystore validation and
column/row security loads to stop cold-cache stampedes
* Preload security rules in BeforeHandle (restheadspec, resolvespec) so
they no longer need a second connection while the read tx is open
* Add pkg/dbtrace: opt-in per-request DB call counting and pool logging
(db_trace.* config, RESOLVESPEC_DB_TRACE_* env), wired into testserver
* Add tests for load dedup, activity throttle and dbtrace
Verify bcrypt passwords in Direct mode and the shipped procedures, hash on
register/reset, ignore client-supplied roles and level at registration and
drop the password from the jwt_login payload. Legacy cleartext upgrade is
opt-in. Row security templates now bind the user as a parameter, validate
identifiers, attach via common.SelectQuery and fail the request if the
filter cannot be attached. ApplyColumnSecurity and GetRowSecurityTemplate
convert panics to errors and the hooks fail closed. Update audit status.
Load column/row security without holding locks across provider calls,
honour pOverwrite with a 30s TTL and pruning, cap tokens per
Authorization header, detach session activity updates with a timeout,
stop OAuth2 cleanup goroutines via Close, move nil-map checks inside
locks, and drop O(n^2) string building. Update audit status.