Add test data injection script with varied runs and encounters

Creates 6 runs across FireRed, Platinum, Emerald, HeartGold, Black, and
Crystal with mixed statuses (failed/completed/active), diverse encounter
states (caught/fainted/missed/evolved/dead), and varied rule configs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.beans/nuzlocke-tracker-ycfs--inject-test-data-into-dev-environment.md

@@ -1,22 +1,38 @@
 ---
 # nuzlocke-tracker-ycfs
 title: Inject test data into dev environment
-status: todo
+status: completed
 type: task
+priority: normal
 created_at: 2026-02-06T09:48:38Z
-updated_at: 2026-02-06T09:48:38Z
+updated_at: 2026-02-07T19:35:11Z
 ---
 
-Create a mechanism to populate the development database with realistic test data for manual testing and development.
+Create a script to populate the development database with realistic test data for manual testing.
 
-## Goals
-- Enable developers to quickly set up a populated dev environment
-- Provide realistic data scenarios for testing UI components
-- Support resetting/refreshing test data easily
+## Requirements
+- Multiple runs across different games with varied statuses:
+  - 2 failed runs (different games, progressed partway)
+  - 2 completed runs (different games, most routes visited)
+  - 2 active/in-progress runs (different games, early-to-mid progress)
+- Each run should have a mix of encounter states:
+  - Caught (alive): with nicknames, catch levels
+  - Caught (dead): with faint_level, death_cause
+  - Fainted (failed to catch)
+  - Missed (ran away / KOd)
+- Some caught Pokemon should be evolved (current_pokemon_id set via the evolutions table)
+- Runs should use varied rule configurations (some with pinwheel clause off, some with hardcore mode, etc.)
+- Respects the one-encounter-per-group constraint (only one child route per parent group gets an encounter, unless pinwheel zones apply)
 
-## Potential Checklist
-- [ ] Define test data requirements (users, playthroughs, encounters, etc.)
-- [ ] Create test data fixtures or factory functions
-- [ ] Add CLI command or script to inject test data
-- [ ] Document how to use the test data injection
-- [ ] Ensure test data can be reset/cleared if needed
+## Implementation
+- Add inject_test_data.py to backend/src/app/seeds/
+- Follows the same async session pattern as run.py
+- Queries DB for real game_ids, route_ids, pokemon_ids, and evolution chains so data is always valid
+- Invocable via python -m app.seeds.inject_test_data (standalone entry block)
+- Clears existing runs+encounters before injecting (idempotent)
+- Prints summary of what was created
+
+## Checklist
+- [x] Create inject_test_data.py with test data injection logic
+- [x] Wire up as standalone script (python -m app.seeds.inject_test_data)
+- [x] Verify it runs cleanly against a seeded database