refactor(scripts): reorganize scripts/ into seed/ and validate/ subfolders

Move 9 init/seed scripts into scripts/seed/ and 7 validation scripts
(+ validators/ subfolder) into scripts/validate/ to reduce clutter in
the root scripts/ directory. Update all references across Makefile,
CI/CD configs, pre-commit hooks, docs (~40 files), and Python imports.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/backend/store-in-token-architecture.md

@@ -525,7 +525,7 @@ The architecture enforces a strict layered pattern for where exceptions should b
 
 ### Enforced by Architecture Validation
 
-The validation script (`scripts/validate_architecture.py`) enforces these rules:
+The validation script (`scripts/validate/validate_architecture.py`) enforces these rules:
 
 **Rule API-003: Endpoints must NOT raise exceptions directly**
 - Detects `raise HTTPException`, `raise InvalidTokenException`, etc. in endpoint files
@@ -542,7 +542,7 @@ Architecture validation runs on every commit:
   hooks:
     - id: validate-architecture
       name: Validate Architecture Patterns
-      entry: python scripts/validate_architecture.py
+      entry: python scripts/validate/validate_architecture.py
       language: python
       pass_filenames: false
       always_run: true
@@ -550,8 +550,8 @@ Architecture validation runs on every commit:
 
 To run manually:
 ```bash
-python scripts/validate_architecture.py  # Full validation
-python scripts/validate_architecture.py -d app/api/v1/store/  # Specific directory
+python scripts/validate/validate_architecture.py  # Full validation
+python scripts/validate/validate_architecture.py -d app/api/v1/store/  # Specific directory
 ```
 
 See `.architecture-rules.yaml` for the complete rule definitions.