perf-review

# Performance Review Framework Evaluate performance impact of changes. This project is a Kotlin MCP server with SQLite via Exposed ORM, handling tool calls synchronously per request. ## Step 1: Hot Path Analysis Identify which hot paths the change touches: - [ ] **Per-request paths** — MCP tool execution (every tool call hits this). New work here adds latency to every request. - [ ] **Per-item loops** — operations that iterate over items (search, overview, stalled-item detection). N+1 patterns here scale poorly. - [ ] **Startup path** — server initialization, database schema creation, config loading. Affects container startup time. - [ ] **Background operations** — cascade detection, dependency resolution. Runs inline, not async. ## Step 2: Database Query Patterns - [ ] **N+1 queries** — does the change add a query inside a loop? (e.g., `countChildrenByRole` per child in overview). Count total queries for a typical operation. - [ ] **Full table scans** — any `selectAll()` without filters on large tables? - [ ] **Missing indexes** — new filter conditions that would benefit from an index? - [ ] **Transaction scope** — are transactions held open longer than necessary? - [ ] **Aggregate vs fetch-all** — using `SELECT COUNT(*)` with `GROUP BY` vs fetching all rows and counting in memory? ## Step 3: JSON/Serialization Cost - [ ] **Large response payloads** — does the change add fields that significantly increase response size? (e.g., adding `childCounts` to every child in ov...