Remove REST API, keep GraphQL as sole API

- Add missing GraphQL mutations: retryJob, updateAsset, deleteAsset
- Add UpdateAssetRequest and DeleteResult to schema source of truth
- Move Lambda callback endpoint to main.py (only REST endpoint)
- Remove REST routes, pydantic schemas, and deps
- Remove pydantic target from modelgen.json
- Update architecture diagrams and documentation

api/graphql.py

@@ -1,7 +1,7 @@
 """
 GraphQL API using graphene, mounted on FastAPI/Starlette.
 
-Provides the same data as the REST API but via GraphQL queries and mutations.
+Primary API for MPR — all client interactions go through GraphQL.
 Uses Django ORM directly for data access.
 Types are generated from schema/ via modelgen — see api/schema/graphql.py.
 """
@@ -12,11 +12,13 @@ import graphene
 
 from api.schema.graphql import (
     CreateJobInput,
+    DeleteResultType,
     MediaAssetType,
     ScanResultType,
     SystemStatusType,
     TranscodeJobType,
     TranscodePresetType,
+    UpdateAssetInput,
 )
 from core.storage import BUCKET_IN, list_objects
 
@@ -238,10 +240,83 @@ class CancelJob(graphene.Mutation):
         return job
 
 
+class RetryJob(graphene.Mutation):
+    class Arguments:
+        id = graphene.UUID(required=True)
+
+    Output = TranscodeJobType
+
+    def mutate(self, info, id):
+        from mpr.media_assets.models import TranscodeJob
+
+        try:
+            job = TranscodeJob.objects.get(id=id)
+        except TranscodeJob.DoesNotExist:
+            raise Exception("Job not found")
+
+        if job.status != "failed":
+            raise Exception("Only failed jobs can be retried")
+
+        job.status = "pending"
+        job.progress = 0
+        job.error_message = None
+        job.save(update_fields=["status", "progress", "error_message"])
+        return job
+
+
+class UpdateAsset(graphene.Mutation):
+    class Arguments:
+        id = graphene.UUID(required=True)
+        input = UpdateAssetInput(required=True)
+
+    Output = MediaAssetType
+
+    def mutate(self, info, id, input):
+        from mpr.media_assets.models import MediaAsset
+
+        try:
+            asset = MediaAsset.objects.get(id=id)
+        except MediaAsset.DoesNotExist:
+            raise Exception("Asset not found")
+
+        update_fields = []
+        if input.comments is not None:
+            asset.comments = input.comments
+            update_fields.append("comments")
+        if input.tags is not None:
+            asset.tags = input.tags
+            update_fields.append("tags")
+
+        if update_fields:
+            asset.save(update_fields=update_fields)
+
+        return asset
+
+
+class DeleteAsset(graphene.Mutation):
+    class Arguments:
+        id = graphene.UUID(required=True)
+
+    Output = DeleteResultType
+
+    def mutate(self, info, id):
+        from mpr.media_assets.models import MediaAsset
+
+        try:
+            asset = MediaAsset.objects.get(id=id)
+            asset.delete()
+            return DeleteResultType(ok=True)
+        except MediaAsset.DoesNotExist:
+            raise Exception("Asset not found")
+
+
 class Mutation(graphene.ObjectType):
     scan_media_folder = ScanMediaFolder.Field()
     create_job = CreateJob.Field()
     cancel_job = CancelJob.Field()
+    retry_job = RetryJob.Field()
+    update_asset = UpdateAsset.Field()
+    delete_asset = DeleteAsset.Field()
 
 
 # ---------------------------------------------------------------------------