fix(fusion_accounting_followup): seeded levels + migration idempotency

- test_create_minimal/negative_delay used sequence=1, which now collides
  with the seeded Friendly Reminder level. Use sequences 901/902.
- migration backfill: search by name (not raw seq) for idempotency,
  allocate sequence as max(existing)+1 to avoid both seed clashes and
  within-batch collisions when Enterprise has duplicate sequence values.

Made-with: Cursor

fusion_accounting_followup/models/fusion_migration_wizard.py

@@ -37,31 +37,38 @@ class FusionMigrationWizard(models.TransientModel):
             result['errors'].append(f"Enterprise search failed: {e}")
             return result
 
+        # Pick a starting offset that doesn't clash with anything already in
+        # fusion_followup_level (seeded defaults at 1..3 plus any prior
+        # migration runs). We allocate a unique sequence per Enterprise line
+        # by max(existing) + 1, ensuring idempotency + within-batch uniqueness.
+        existing_max = max(FusionLevel.search([]).mapped('sequence') or [100])
+        next_seq = max(existing_max + 1, 101)
+
         # Map Enterprise tone-ish fields to ours
         for ee in ee_records:
             try:
-                # Idempotency: skip if a level with same sequence + name already exists
-                seq = getattr(ee, 'sequence', None) or 50
-                name = getattr(ee, 'name', None) or f"Migrated Level {seq}"
-                existing = FusionLevel.search([
-                    ('sequence', '=', seq),
-                    ('name', '=', name),
-                ], limit=1)
+                raw_seq = getattr(ee, 'sequence', None) or 50
+                name = getattr(ee, 'name', None) or f"Migrated Level {raw_seq}"
+                # Idempotency: skip if a level with same name was already
+                # backfilled in a prior migration run.
+                existing = FusionLevel.search([('name', '=', name)], limit=1)
                 if existing:
                     result['skipped'] += 1
                     continue
 
                 delay = getattr(ee, 'delay', None) or getattr(ee, 'delay_days', 7)
                 # Enterprise tone heuristic: scale by sequence
-                tone = 'gentle' if seq <= 1 else 'firm' if seq <= 2 else 'legal'
+                tone = 'gentle' if raw_seq <= 1 else 'firm' if raw_seq <= 2 else 'legal'
 
-                FusionLevel.create({
-                    'name': name,
-                    'sequence': seq + 100,  # offset so we don't clash with seeded defaults
-                    'delay_days': delay,
-                    'tone': tone,
-                    'active': True,
-                })
+                with self.env.cr.savepoint():
+                    FusionLevel.create({
+                        'name': name,
+                        'sequence': next_seq,
+                        'delay_days': delay,
+                        'tone': tone,
+                        'active': True,
+                    })
+                next_seq += 1
                 result['created'] += 1
             except Exception as e:
                 result['errors'].append(f"Line {ee.id}: {e}")