Refactor demo session architecture: consolidate metadata into fixture files

This commit refactors the demo session architecture to consolidate all demo
configuration data into the fixture files, removing redundant metadata files.

## Changes Made:

### 1. Data Consolidation
- **Removed**: `shared/demo/metadata/demo_users.json`
- **Removed**: `shared/demo/metadata/tenant_configs.json`
- **Updated**: Merged all user data into `02-auth.json` files
- **Updated**: Merged all tenant config data into `01-tenant.json` files

### 2. Enterprise Parent Tenant Updates
- Updated owner name to "Director" (matching auth fixtures)
- Added description field matching tenant_configs.json
- Added `base_tenant_id` to all child tenant entries
- Now includes all 5 child locations (Madrid, Barcelona, Valencia, Seville, Bilbao)

### 3. Professional Tenant Updates
- Added description field from tenant_configs.json
- Ensured consistency with auth fixtures

### 4. Code Updates
- **services/tenant/app/api/internal_demo.py**:
  - Fixed child tenant staff members to use enterprise parent users
  - Changed from professional staff IDs to enterprise staff IDs (Laura López, José Martínez, Francisco Moreno)

- **services/demo_session/app/core/config.py**:
  - Updated DEMO_ACCOUNTS configuration with all 5 child outlets
  - Updated enterprise tenant name and email to match fixtures
  - Added descriptions for all child locations

- **gateway/app/middleware/demo_middleware.py**:
  - Updated comments to reference fixture files as source of truth
  - Clarified that owner IDs come from 01-tenant.json files

- **frontend/src/stores/useTenantInitializer.ts**:
  - Updated tenant names and descriptions to match fixture files
  - Added comments linking to source fixture files

## Benefits:

1. **Single Source of Truth**: All demo data now lives in fixture files
2. **Consistency**: No more sync issues between metadata and fixtures
3. **Maintainability**: Easier to update demo data (one place per tenant type)
4. **Clarity**: Clear separation between template data (fixtures) and runtime config

## Enterprise Demo Fix:

The enterprise owner is now correctly added as a member of all child tenants, fixing
the issue where the tenant switcher didn't show parent/child tenants and the
establishments page didn't load tenants for the demo enterprise user.

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

shared/demo/fixtures/enterprise/parent/01-tenant.json

@@ -1,18 +1,19 @@
 {
   "tenant": {
     "id": "80000000-0000-4000-a000-000000000001",
-    "name": "Panader\u00eda Artesana Espa\u00f1a - Central",
+    "name": "Panadería Artesana España - Central",
     "subscription_tier": "enterprise",
     "tenant_type": "parent",
     "email": "central@panaderiaartesana.es",
     "subdomain": "artesana-central",
+    "description": "Central production facility and parent tenant for Panadería Artesana España multi-location bakery chain",
     "is_active": true,
     "created_at": "2024-01-01T00:00:00Z",
     "updated_at": "2024-01-01T00:00:00Z"
   },
   "owner": {
     "id": "d2e3f4a5-b6c7-48d9-e0f1-a2b3c4d5e6f7",
-    "name": "Carlos Rodr\u00edguez",
+    "name": "Director",
     "email": "director@panaderiaartesana.es",
     "role": "owner"
   },
@@ -58,6 +59,7 @@
     {
       "id": "A0000000-0000-4000-a000-000000000001",
       "name": "Madrid - Salamanca",
+      "base_tenant_id": "A0000000-0000-4000-a000-000000000001",
       "location": {
         "city": "Madrid",
         "zone": "Salamanca",
@@ -69,6 +71,7 @@
     {
       "id": "B0000000-0000-4000-a000-000000000001",
       "name": "Barcelona - Eixample",
+      "base_tenant_id": "B0000000-0000-4000-a000-000000000001",
       "location": {
         "city": "Barcelona",
         "zone": "Eixample",
@@ -80,6 +83,7 @@
     {
       "id": "C0000000-0000-4000-a000-000000000001",
       "name": "Valencia - Ruzafa",
+      "base_tenant_id": "C0000000-0000-4000-a000-000000000001",
       "location": {
         "city": "Valencia",
         "zone": "Ruzafa",
@@ -91,6 +95,7 @@
     {
       "id": "D0000000-0000-4000-a000-000000000001",
       "name": "Seville - Triana",
+      "base_tenant_id": "D0000000-0000-4000-a000-000000000001",
       "location": {
         "city": "Seville",
         "zone": "Triana",
@@ -102,6 +107,7 @@
     {
       "id": "E0000000-0000-4000-a000-000000000001",
       "name": "Bilbao - Casco Viejo",
+      "base_tenant_id": "E0000000-0000-4000-a000-000000000001",
       "location": {
         "city": "Bilbao",
         "zone": "Casco Viejo",
@@ -111,4 +117,4 @@
       "description": "Basque region location with focus on quality and local culture"
     }
   ]
-}
+}

shared/demo/fixtures/enterprise/parent/02-auth.json

@@ -4,6 +4,7 @@
       "id": "d2e3f4a5-b6c7-48d9-e0f1-a2b3c4d5e6f7",
       "tenant_id": "80000000-0000-4000-a000-000000000001",
       "name": "Director",
+      "full_name": "Director",
       "email": "director@panaderiaartesana.es",
       "role": "owner",
       "is_active": true,

shared/demo/fixtures/professional/01-tenant.json

@@ -6,6 +6,7 @@
     "email": "demo.professional@panaderiaartesana.com",
     "subscription_tier": "professional",
     "tenant_type": "standalone",
+    "description": "Professional tier demo tenant for bakery operations",
     "is_active": true,
     "created_at": "2025-01-15T06:00:00Z",
     "updated_at": "2025-01-15T06:00:00Z"