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_files_view_extended.py

@@ -142,7 +142,7 @@ class TestFileDetailPage:
         db_session.commit()
 
         # Test file detail page
-        response = client.get(f"/files/{file_record.id}/detail")
+        response = client.get(f"/files/{file_record.id}/process")
         assert response.status_code == 200
         content = response.text
         assert "test.pdf" in content
@@ -150,7 +150,7 @@ class TestFileDetailPage:
     def test_file_detail_page_with_missing_file(self, client: TestClient, db_session):
         """Test file detail page with non-existent file"""
         # Try to access non-existent file
-        response = client.get("/files/99999/detail")
+        response = client.get("/files/99999/process")
         assert response.status_code == 200
         content = response.text
         assert "not found" in content.lower()
@@ -193,7 +193,7 @@ class TestFileDetailPage:
         db_session.commit()
 
         # Test file detail page
-        response = client.get(f"/files/{file_record.id}/detail")
+        response = client.get(f"/files/{file_record.id}/process")
         assert response.status_code == 200
         content = response.text
         assert "create_file_record" in content
@@ -232,7 +232,7 @@ class TestFileDetailPage:
         db_session.commit()
 
         # Test file detail page
-        response = client.get(f"/files/{file_record.id}/detail")
+        response = client.get(f"/files/{file_record.id}/process")
         assert response.status_code == 200
         content = response.text
         # Should show metadata