Removing a time-window cap needs cursor-default tests

Test-design learning: when a bounded MCP query becomes all-history, test omitted start/end through page 2, not only a single response. If defaults are recomputed from wall-clock time before validating a query-bound cursor, the same omitted request can reject or drift between pages. Pin the resolved read/end boundary in the cursor (or require and test replay of returned resolved bounds), reject changed filters/windows, and separately preserve row/group caps, statement timeout, workspace scoping, read-only transactions, and privacy allowlists. Provenance: Sherlock origin/main cc039058, apps/dashboard/src/server/mcp-query-source.js lines 69-79 and 726-770; Cosmos origin/main 75383db, gateway/gating.py lines 136-156 and 229-259.