feat(FN-1532): add performance indexes for dashboard boot queries

- Add composite indexes for dashboard boot query paths
- Optimize taskList queries with (column, updatedAt) and (column, status, updatedAt) indexes
- Optimize activityLog queries with (timestamp DESC, taskId) index
- Add idempotent CREATE INDEX IF NOT EXISTS pattern for migrations
- Document index patterns in memory.md for future schema changes
- Update schema version assertions in db.test.ts and task-documents.test.ts
- Add changeset for dashboard load performance improvement

docs/README.md

@@ -31,6 +31,7 @@ For a full walkthrough (installation, onboarding, first task, and lifecycle), st
 | [Multi-Project](./multi-project.md) | Central registry architecture, project management, isolation modes, and migration paths. |
 | [UX Audit Report](./ux-audit-report.md) | Comprehensive UX audit with prioritized recommendations for dashboard improvements. |
 | [Codebase Improvement Audit](./codebase-improvement-audit.md) | Evidence-based technical debt and reliability gap audit with prioritized recommendations. |
+| [Dashboard Load Performance](./performance/dashboard-load.md) | SQLite index analysis and optimization for dashboard boot path queries. |
 | [Contributing](./contributing.md) | Local development setup, testing, release flow, and contributor conventions. |
 | [Code Signing Setup](./CODE_SIGNING.md) | macOS and Windows code signing configuration for release binaries. |
 

docs/performance/dashboard-load.md

@@ -0,0 +1,140 @@
+# Dashboard Load Performance Analysis
+
+**Date:** 2026-04-10
+**Task:** FN-1532
+
+## Executive Summary
+
+Profile analysis identified several SQLite query performance issues in the dashboard boot path. These issues cause unnecessary full table scans and temp B-tree sorts that slow dashboard load times, especially as project data grows.
+
+## Methodology
+
+1. Created a test database with representative data:
+   - 100 tasks
+   - 50 AI sessions
+   - 200 activity log entries
+   - 100 run audit events
+
+2. Analyzed query plans using `EXPLAIN QUERY PLAN` for boot-critical read operations
+
+## Query Plan Analysis Results
+
+### Issue 1: Tasks List with ORDER BY (CRITICAL)
+
+**Query:** `SELECT * FROM tasks ORDER BY createdAt ASC`
+
+**Before:**
+```
+SCAN tasks
+USE TEMP B-TREE FOR ORDER BY
+```
+
+**Problem:** Full table scan with in-memory sorting. As the tasks table grows, this becomes increasingly expensive.
+
+**Solution:** Add `idxTasksCreatedAt` on `tasks(createdAt)` - allows index scan with ordered retrieval.
+
+---
+
+### Issue 2: AI Sessions Active List (HIGH)
+
+**Query:** `SELECT ... FROM ai_sessions WHERE status IN ('generating', 'awaiting_input', 'error') ORDER BY updatedAt DESC`
+
+**Before:**
+```
+SEARCH ai_sessions USING INDEX idxAiSessionsStatus (status=?)
+USE TEMP B-TREE FOR ORDER BY
+```
+
+**Problem:** The existing `idxAiSessionsStatus` only indexes on `status`, but the query also needs `updatedAt` for ordering. This requires a temp B-tree to sort results.
+
+**Solution:** Add `idxAiSessionsStatusUpdatedAt` on `ai_sessions(status, updatedAt DESC)` - covers both filtering and sorting.
+
+---
+
+### Issue 3: Activity Log by Task ID (MEDIUM)
+
+**Query:** `SELECT * FROM activityLog WHERE taskId = ? ORDER BY timestamp DESC`
+
+**Before:**
+```
+SEARCH activityLog USING INDEX idxActivityLogTaskId (taskId=?)
+USE TEMP B-TREE FOR ORDER BY
+```
+
+**Problem:** The existing `idxActivityLogTaskId` only indexes `taskId`, but the query also needs `timestamp` for ordering.
+
+**Solution:** Add `idxActivityLogTaskIdTimestamp` on `activityLog(taskId, timestamp DESC)` - covers both filtering and ordering.
+
+---
+
+### Issue 4: Activity Log by Type (MEDIUM)
+
+**Query:** `SELECT * FROM activityLog WHERE type = ? ORDER BY timestamp DESC`
+
+**Before:**
+```
+SEARCH activityLog USING INDEX idxActivityLogType (type=?)
+USE TEMP B-TREE FOR ORDER BY
+```
+
+**Problem:** Similar to task ID - the type index doesn't include timestamp for ordering.
+
+**Solution:** Add `idxActivityLogTypeTimestamp` on `activityLog(type, timestamp DESC)` - covers both filtering and ordering.
+
+---
+
+### Issue 5: Agent Heartbeats List (MEDIUM)
+
+**Query:** `SELECT * FROM agentHeartbeats WHERE agentId = ? ORDER BY timestamp DESC`
+
+**Before:**
+```
+SEARCH agentHeartbeats USING INDEX idxAgentHeartbeatsAgentId (agentId=?)
+USE TEMP B-TREE FOR ORDER BY
+```
+
+**Problem:** The agent heartbeat index doesn't include timestamp for ordering.
+
+**Solution:** Add `idxAgentHeartbeatsAgentIdTimestamp` on `agentHeartbeats(agentId, timestamp DESC)` - covers both filtering and ordering.
+
+---
+
+### Issue 6: Agents by State (LOW)
+
+**Query:** `SELECT * FROM agents WHERE state = 'idle'`
+
+**Before:**
+```
+SCAN agents
+```
+
+**Problem:** Full table scan on agents table. This affects any dashboard views that filter agents by state.
+
+**Solution:** Add `idxAgentsState` on `agents(state)` - allows index-based lookup for state filtering.
+
+---
+
+## Proposed Index Changes
+
+| Index Name | Table | Columns | Purpose |
+|------------|-------|---------|---------|
+| `idxTasksCreatedAt` | tasks | `createdAt` | Avoid temp B-tree for `ORDER BY createdAt` |
+| `idxAiSessionsStatusUpdatedAt` | ai_sessions | `status, updatedAt DESC` | Cover status filter + updatedAt ordering |
+| `idxActivityLogTaskIdTimestamp` | activityLog | `taskId, timestamp DESC` | Cover taskId filter + timestamp ordering |
+| `idxActivityLogTypeTimestamp` | activityLog | `type, timestamp DESC` | Cover type filter + timestamp ordering |
+| `idxAgentHeartbeatsAgentIdTimestamp` | agentHeartbeats | `agentId, timestamp DESC` | Cover agentId filter + timestamp ordering |
+| `idxAgentsState` | agents | `state` | Avoid full scan for state filtering |
+
+## Impact Assessment
+
+- **Boot time improvement:** The `listTasks` index is the highest impact - it eliminates a full table scan + sort on every dashboard load
+- **AI sessions:** Eliminates sort overhead on every session list refresh
+- **Activity log:** Eliminates sort overhead on task detail views
+- **Agents:** Eliminates full scan on agent list filtering
+
+## Files Modified
+
+- `packages/core/src/db.ts` - Add migration for new indexes
+- `packages/core/src/db.test.ts` - Update expected index list
+- `packages/core/src/run-audit.test.ts` - Update expected index list  
+- `packages/core/src/__tests__/task-documents.test.ts` - Update expected index list