Github Copilot service realignment & cleanup

docs/ver4/architecture_v4.md

@@ -68,15 +68,31 @@ Responsibilities:
 ### Domain and Service Layer
 
 - `src/transcription/db/models.py`
-- `src/transcription/services/*.py`
+- `src/transcription/services/documents.py`
+- `src/transcription/services/sources.py`
+- `src/transcription/services/jobs.py`
+- `src/transcription/services/people.py`
+- `src/transcription/services/workflows.py`
 
 Responsibilities:
 
-- Manage transactional operations for documents, people, types, links, sources, jobs, and job sources.
+- Keep one primary service boundary per aggregate: Documents, Sources, Jobs, and People.
+- Documents own document records and the document-type registry.
+- Sources own source records, revisions, source media formats, MIME resolution, and page execution evidence.
+- Jobs own job lifecycle state and transitions.
+- People own person records, relationship roles, document-person links, and portrait media.
 - Apply deterministic conflict handling for relationship-role writes.
 - Use set-based synchronization for many-to-many relationship updates.
 - Resolve and validate registry-backed document types.
 
+### Source Media Policy
+
+- `services/sources.py` is the single authority for accepted Source extensions and canonical MIME types.
+- Storage and provider payload loading must call the same Source validation functions.
+- Supported Source formats are JPEG, PNG, TIFF, and PDF.
+- Upload is an interface action, not a domain aggregate. Service names, errors, and workflow variables use
+  `Source` terminology; compatibility aliases may remain temporarily at old import boundaries.
+
 ### Infrastructure Layer
 
 - `src/transcription/db/**`