refactor: Remove TEXT fields and use only reasoning_data for i18n

Completed the migration to structured reasoning_data for multilingual
dashboard support. Removed hardcoded TEXT fields (reasoning, consequence)
and updated all related code to use JSONB reasoning_data.

Changes:

1. Models Updated (removed TEXT fields):
   - PurchaseOrder: Removed reasoning, consequence TEXT columns
   - ProductionBatch: Removed reasoning TEXT column
   - Both now use only reasoning_data (JSONB/JSON)

2. Dashboard Service Updated:
   - Changed to return reasoning_data instead of TEXT fields
   - Creates default reasoning_data if missing
   - PO actions: reasoning_data with type and parameters
   - Production timeline: reasoning_data for each batch

3. Unified Schemas Updated (no separate migration):
   - services/procurement/migrations/001_unified_initial_schema.py
   - services/production/migrations/001_unified_initial_schema.py
   - Removed reasoning/consequence columns from table definitions
   - Updated comments to reflect i18n approach

Database Schema:
- purchase_orders: Only reasoning_data (JSONB)
- production_batches: Only reasoning_data (JSON)

Backend now generates:
{
  "type": "low_stock_detection",
  "parameters": {
    "supplier_name": "Harinas del Norte",
    "days_until_stockout": 3,
    ...
  },
  "consequence": {
    "type": "stockout_risk",
    "severity": "high"
  }
}

Next Steps:
- Frontend: Create i18n translation keys
- Frontend: Update components to translate reasoning_data
- Test multilingual support (ES, EN, CA)

services/procurement/app/models/purchase_order.py

@@ -119,17 +119,30 @@ class PurchaseOrder(Base):
     internal_notes = Column(Text, nullable=True)  # Not shared with supplier
     terms_and_conditions = Column(Text, nullable=True)
 
-    # JTBD Dashboard: Reasoning and consequences for user transparency
-    # Deferred loading to prevent breaking queries when columns don't exist yet
-    reasoning = deferred(Column(Text, nullable=True))  # Why this PO was created (e.g., "Low flour stock (2 days left)")
-    consequence = deferred(Column(Text, nullable=True))  # What happens if not approved (e.g., "Stock out risk in 48 hours")
-    reasoning_data = deferred(Column(JSONB, nullable=True))  # Structured reasoning data
-    # reasoning_data structure: {
-    #   "trigger": "low_stock" | "forecast_demand" | "manual",
-    #   "ingredients_affected": [{"id": "uuid", "name": "Flour", "current_stock": 10, "days_remaining": 2}],
-    #   "orders_impacted": [{"id": "uuid", "product": "Baguette", "quantity": 100}],
-    #   "urgency_score": 0-100,
-    #   "estimated_stock_out_date": "2025-11-10T00:00:00Z"
+    # JTBD Dashboard: Structured reasoning data for i18n support
+    # Backend stores structured data, frontend translates using i18n
+    reasoning_data = Column(JSONB, nullable=True)  # Structured reasoning data for multilingual support
+    # reasoning_data structure (see shared/schemas/reasoning_types.py):
+    # {
+    #   "type": "low_stock_detection" | "forecast_demand" | "safety_stock_replenishment" | etc.,
+    #   "parameters": {
+    #     "supplier_name": "Harinas del Norte",
+    #     "product_names": ["Flour Type 55", "Flour Type 45"],
+    #     "days_until_stockout": 3,
+    #     "current_stock": 45.5,
+    #     "required_stock": 200
+    #   },
+    #   "consequence": {
+    #     "type": "stockout_risk",
+    #     "severity": "high",
+    #     "impact_days": 3,
+    #     "affected_products": ["Baguette", "Croissant"]
+    #   },
+    #   "metadata": {
+    #     "trigger_source": "orchestrator_auto",
+    #     "forecast_confidence": 0.85,
+    #     "ai_assisted": true
+    #   }
     # }
 
     # Audit fields