In this PR we're optimizing the GetTemplateAppInsightsByTemplate query by pre-filtering out apps which do not have an active session during the start/end time window.
Note: as of Nov 4 this is our most expensive query internally in terms of DB load though it only is called ~900 times in a 24h period it has a 1s average execution time and minimum of ~400ms.

This query currently looks at all entries in workspace_app_stats (IIUC each row is an app session), then splits them into per-minute buckets before filtering out buckets that do not fall within our start/end time window. This leads to expensive query processing time to do sequential scans and joins for various data that will eventually just be thrown away due to being outside the time range.

Instead, we can pre-filter out the majority of the buckets that need to be thrown away by only retrieving entries from workspace_app_stats for sessions where at least some portion of the sessions active time range is within our start/end time range. We keep the existing filter of buckets to ensure we still filter out buckets that fall outside the time range.

The default time window for the query is 5 minutes, so start = time.Now() - 5m and end = time.Now(). Using EXPLAIN and a specific 5 minute time window from earlier today (2025-11-03 18:00–18:05 UTC) the difference is pretty obvious:

• Current: 444.8 ms, shared buffers 6,385, Parallel Seq Scan on workspace_app_stats, generate_series called ~67,380 times.
• Optimized: 16.09 ms, shared buffers 1,782, only 4 generate_series calls.

I compared/verified the output of the queries, the filtered rows and distinct app names/template IDs, and that terminal is still not considered an app.