Add genlocke leg progression with advance endpoint and run context

When a run belonging to a genlocke is completed or failed, the genlocke
status updates accordingly. The run detail API now includes genlocke
context (leg order, total legs, genlocke name). A new advance endpoint
creates the next leg's run, and the frontend shows genlocke-aware UI
including a "Leg X of Y" banner, advance button, and contextual
messaging in the end-run modal.

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

.beans/nuzlocke-tracker-25mh--genlocke-tracking.md

@@ -80,8 +80,8 @@ A dedicated page showing:
 - [x] The first leg starts automatically upon genlocke creation
 - [ ] Each leg is a full nuzlocke run, tracked identically to standalone runs
 - [ ] Completing a leg triggers a transfer step where surviving Pokemon can be carried forward
-- [ ] Failing a leg marks the entire genlocke as failed
-- [ ] Completing the final leg marks the genlocke as completed
+- [x] Failing a leg marks the entire genlocke as failed
+- [x] Completing the final leg marks the genlocke as completed
 - [ ] A genlocke overview page shows progress, configuration, cumulative stats, lineage, and graveyard
 - [ ] Transferred Pokemon appear as eggs (base form, level 1) in the next leg
 - [ ] Pokemon lineage is trackable across multiple legs

.beans/nuzlocke-tracker-thbz--genlocke-leg-progression.md

@@ -1,11 +1,11 @@
 ---
 # nuzlocke-tracker-thbz
 title: Genlocke leg progression
-status: todo
+status: in-progress
 type: feature
 priority: normal
 created_at: 2026-02-09T07:42:33Z
-updated_at: 2026-02-09T07:45:55Z
+updated_at: 2026-02-09T08:42:15Z
 parent: nuzlocke-tracker-25mh
 blocking:
     - nuzlocke-tracker-p74f
@@ -45,12 +45,12 @@ Handle the sequential progression of legs within a genlocke. When one leg is com
 - After completion, redirect to the transfer step (or to the genlocke overview if it was the final leg)
 
 ## Checklist
-- [ ] Add backend logic to detect when a completed/failed run belongs to a genlocke (query GenlockeLeg by run_id)
-- [ ] On run completion: update GenlockeLeg status, determine if there's a next leg
-- [ ] On run failure: mark the genlocke as failed, prevent further leg creation
-- [ ] On final leg completion: mark the genlocke as completed
-- [ ] Implement `POST /api/v1/genlockes/{id}/legs/{leg_order}/advance` endpoint to create the next leg's run
-- [ ] Add genlocke context to the run detail API response (genlocke name, leg number, total legs) when the run belongs to a genlocke
-- [ ] Update the frontend run page header to show "Leg X of Y — {Genlocke Name}" when applicable
-- [ ] Update the run completion flow on the frontend to detect genlocke membership and redirect to transfer step instead of the standard completion screen
+- [x] Add backend logic to detect when a completed/failed run belongs to a genlocke (query GenlockeLeg by run_id)
+- [x] On run completion: update GenlockeLeg status, determine if there's a next leg
+- [x] On run failure: mark the genlocke as failed, prevent further leg creation
+- [x] On final leg completion: mark the genlocke as completed
+- [x] Implement `POST /api/v1/genlockes/{id}/legs/{leg_order}/advance` endpoint to create the next leg's run
+- [x] Add genlocke context to the run detail API response (genlocke name, leg number, total legs) when the run belongs to a genlocke
+- [x] Update the frontend run page header to show "Leg X of Y — {Genlocke Name}" when applicable
+- [x] Update the run completion flow on the frontend to detect genlocke membership and redirect to transfer step instead of the standard completion screen
 - [ ] Handle edge case: what happens if a genlocke run is manually deleted?