feat: Script Generator Phase 1+2 — backend, engine, API, frontend, template editor, parameter detector

Complete Script Generator feature including:

Backend:
- ScriptCategory, ScriptTemplate, ScriptGeneration models
- ScriptTemplateEngine with substitution, filters, sanitization
- CRUD + share API endpoints with permission checks
- Integration tests for permissions and sharing
- Migration 057 with AD User Management seed templates

Frontend — Script Library:
- Browse templates with category tabs and search
- Configure pane with parameter form and script generation
- Script preview with live substitution and copy/download
- scriptGeneratorStore Zustand store

Frontend — Template Editor:
- Full CRUD form with metadata, script body (Monaco Editor), parameters
- ParameterSchemaBuilder with visual builder + JSON toggle
- ScriptManagePage with routing and nav link

Frontend — Parameter Detector:
- Client-side PowerShell parameter detection engine
- Detects script-level param() blocks and variable assignments
- Type inference from PS type annotations and value patterns
- ParameterDetectorStepper one-by-one review UI with accept/skip

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/alembic/env.py

@@ -18,6 +18,7 @@ from app.models.survey_response import SurveyResponse
 from app.models.survey_invite import SurveyInvite
 from app.models.ai_suggestion import AISuggestion  # noqa: F401
 from app.models.kb_import import KBImport, KBImportNode  # noqa: F401
+from app.models.script_template import ScriptCategory, ScriptTemplate, ScriptGeneration  # noqa: F401
 from app.core.config import settings
 
 # this is the Alembic Config object