Add name suggestion engine with API endpoint and tests

Expand services/naming.py with suggest_names() that picks random words
from a category while excluding nicknames already used in the run. Add
GET /runs/{run_id}/name-suggestions?count=10 endpoint that reads the
run's naming_scheme and returns filtered suggestions. Includes 12 unit
tests covering selection, exclusion, exhaustion, and cross-category
independence.

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

.beans/nuzlocke-tracker-igl3--name-generation.md

@@ -5,7 +5,7 @@ status: todo
 type: epic
 priority: normal
 created_at: 2026-02-05T13:45:15Z
-updated_at: 2026-02-11T20:41:56Z
+updated_at: 2026-02-11T20:44:23Z
 ---
 
 Implement a dictionary-based nickname generation system for Nuzlocke runs. Instead of using an LLM API to generate names on the fly, provide a static dictionary of words categorised by theme. A word can belong to multiple categories, making it usable across different naming schemes.
@@ -28,7 +28,7 @@ Implement a dictionary-based nickname generation system for Nuzlocke runs. Inste
 ## Success Criteria
 
 - [x] Word dictionary data file exists with multiple categories, each containing 150-200 words
-- [ ] Name suggestion engine picks random names from the selected category, avoiding duplicates already used in the run
+- [x] Name suggestion engine picks random names from the selected category, avoiding duplicates already used in the run
 - [ ] Encounter registration UI shows 5-10 clickable name suggestions
 - [ ] User can regenerate suggestions if none fit
 - [x] User can select a naming scheme per run