P3.2: Move RunDue/RunNow/startRunLocked/executeRun into app/run.go

Extracts the four dispatch functions and their private helper
runningOutput into a dedicated file so operations.go stays focused on
CRUD and settings. No behaviour change; shared helpers (prependLog,
refreshNextRunLocked, etc.) remain in operations.go where other
operations already call them.

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

docs/PRE-RELEASE-TASKS.md

@@ -95,7 +95,7 @@ These land together because both edit `domain/job.go` and `storage/store.go`.
 
 ### Phase 3 — Task-queue model + settings
 - [x] P3.1 — Config/runtime fields + defaults
-- [ ] P3.2 — Split dispatch into `app/run.go`
+- [x] P3.2 — Split dispatch into `app/run.go`
 - [ ] P3.3 — Rework `RunDue`/`executeRun` for mode + overlap policy
 - [ ] P3.4 — Settings Queue selects
 - [ ] P3.5 — Queue tests