GitHub Issue 1534: Cap row counts for React grid pagination

[XingY]

Rationale

Bound a grid's pagination row count at a caller-supplied maxCount so the count query is fixed-cost on large tables. A COUNT(*) over Sample Type / Data Class tables can be expensive; when a client opts in, the server counts no further than the cap and flags the result as capped, and an experimental flag lets an admin restore exact counts.

Related Pull Requests

• GitHub Issue 1534: Cap row counts for React grid pagination labkey-api-js#225
• GitHub Issue 1534: Cap row counts for React grid pagination labkey-ui-components#2074
• GitHub Issue 1534: Cap row counts for React grid pagination #8029
• https://github.com/LabKey/limsModules/pull/2471
• GitHub Issue 1534: Cap row counts for React grid pagination testAutomation#3189

Changes

• Accept a maxCount query setting from the API and URL parameters, defaulting to an exact (unbounded) count when absent.
• When the only aggregate is the row count and a cap is set, bound the inner select so the count stops early, and report the capped total plus a "capped" indicator in the query API response.
• Leave summary-statistic queries and exact counts unchanged.
• Add an experimental feature flag to restore legacy exact grid row counts, surfaced in the page context for the client.