Refactor query/procedure/query store stats to phased DECOMPRESS approach

All three grid queries now use a 3-phase pattern:
1. Aggregate numerics into temp table (no DECOMPRESS)
2. Sum across lifetimes, rank TOP 500
3. OUTER APPLY to decompress text/plan for only the 500 winners

On a 742K-row query_stats table, this reduces DECOMPRESS calls from
742K to 500 — eliminating the 16+ minute query times reported in #835.

Matches the existing phased pattern used by the MCP query tools.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: erikdarlingdata