feat: add company detail page and transfer ownership UI

- Add company-detail.html with status cards, info sections, vendors list
- Add company-edit.html with transfer ownership modal
- Add company-detail.js and company-edit.js
- Add user search autocomplete for transfer ownership
- Add inline validation errors for transfer form
- Add View button to companies list page
- Add route for /admin/companies/{id} detail page

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/routes/admin_pages.py

@@ -12,6 +12,9 @@ Routes:
 - GET /              → Redirect to /admin/login
 - GET /login         → Admin login page (no auth)
 - GET /dashboard     → Admin dashboard (auth required)
+- GET /companies     → Company list page (auth required)
+- GET /companies/create → Create company form (auth required)
+- GET /companies/{company_id}/edit → Edit company form (auth required)
 - GET /vendors       → Vendor list page (auth required)
 - GET /vendors/create → Create vendor form (auth required)
 - GET /vendors/{vendor_code} → Vendor details (auth required)
@@ -152,6 +155,50 @@ async def admin_company_create_page(
     )
 
 
+@router.get(
+    "/companies/{company_id}", response_class=HTMLResponse, include_in_schema=False
+)
+async def admin_company_detail_page(
+    request: Request,
+    company_id: int = Path(..., description="Company ID"),
+    current_user: User = Depends(get_current_admin_from_cookie_or_header),
+    db: Session = Depends(get_db),
+):
+    """
+    Render company detail view.
+    """
+    return templates.TemplateResponse(
+        "admin/company-detail.html",
+        {
+            "request": request,
+            "user": current_user,
+            "company_id": company_id,
+        },
+    )
+
+
+@router.get(
+    "/companies/{company_id}/edit", response_class=HTMLResponse, include_in_schema=False
+)
+async def admin_company_edit_page(
+    request: Request,
+    company_id: int = Path(..., description="Company ID"),
+    current_user: User = Depends(get_current_admin_from_cookie_or_header),
+    db: Session = Depends(get_db),
+):
+    """
+    Render company edit form.
+    """
+    return templates.TemplateResponse(
+        "admin/company-edit.html",
+        {
+            "request": request,
+            "user": current_user,
+            "company_id": company_id,
+        },
+    )
+
+
 # ============================================================================
 # VENDOR MANAGEMENT ROUTES
 # ============================================================================