refactor(views): split file views into summary, detail, process, and annotations pages

- /files/<id> → new summary page with navigation cards
- /files/<id>/detail → document detail with metadata, preview, text
- /files/<id>/process → processing pipeline status and history
- /files/<id>/annotations → comments & annotations with EmbedPDF viewer
- /files/<id>/comments → redirects to /annotations
- Added embed-pdf-viewer as git submodule for PDF annotation viewer
- Updated all navigation links across templates
- Updated all tests to use new URL structure

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
Agent-Logs-Url: https://github.com/christianlouis/DocuElevate/sessions/12276514-bd3d-4e3e-84d9-5977d1f82b19

tests/test_file_detail_endpoints.py

@@ -447,7 +447,7 @@ class TestFileDetailView:
         db_session.commit()
 
         # Test detail view
-        response = client.get(f"/files/{file_record.id}/detail")
+        response = client.get(f"/files/{file_record.id}/process")
         assert response.status_code == 200
         # Check that response contains HTML with file information
         assert b"File Information" in response.content
@@ -504,7 +504,7 @@ class TestFileDetailView:
         db_session.commit()
 
         # Test detail view
-        response = client.get(f"/files/{file_record.id}/detail")
+        response = client.get(f"/files/{file_record.id}/process")
         assert response.status_code == 200
         # Check that response contains branching visualization elements
         assert b"Process Flow Visualization" in response.content
@@ -514,7 +514,7 @@ class TestFileDetailView:
 
     def test_file_detail_view_nonexistent(self, client: TestClient):
         """Test file detail view for nonexistent file."""
-        response = client.get("/files/99999/detail")
+        response = client.get("/files/99999/process")
         assert response.status_code == 200  # Returns page with error message
         assert b"not found" in response.content.lower()