feat(compliance): add GDPR, HIPAA, SOC2 compliance templates with one-click apply and dashboard

- Add ComplianceTemplate model in app/models.py
- Create database migration 027_add_compliance_templates
- Add compliance_enabled feature flag to config and settings metadata
- Create compliance_service.py with pre-built template definitions and evaluation
- Create compliance API endpoints (list, get, apply, status, summary)
- Create compliance admin view and dashboard template
- Add compliance link to admin navigation (desktop and mobile)
- Seed compliance templates at application startup
- Add comprehensive tests (29 passing)

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/config.py

@@ -484,6 +484,14 @@ class Settings(BaseSettings):
 
     # Feature flags
     allow_file_delete: bool = True  # Default to allowing file deletion from database
+    compliance_enabled: bool = Field(
+        default=True,
+        description=(
+            "Enable the compliance templates dashboard (GDPR, HIPAA, SOC 2). "
+            "When enabled, admins can view compliance status and apply "
+            "pre-built regulatory configurations. Default: True."
+        ),
+    )
 
     # PDF/A archival conversion settings
     enable_pdfa_conversion: bool = Field(