feat: initial shared library extraction

Contains shared infrastructure for all coop services:
- shared/ (factory, urls, user_loader, context, internal_api, jinja_setup)
- models/ (User, Order, Calendar, Ticket, Product, Ghost CMS)
- db/ (SQLAlchemy async session, base)
- suma_browser/app/ (csrf, middleware, errors, authz, redis_cacher, payments, filters, utils)
- suma_browser/templates/ (shared base layouts, macros, error pages)
- static/ (CSS, JS, fonts, images)
- alembic/ (database migrations)
- config/ (app-config.yaml)
- editor/ (Lexical editor Node.js build)
- requirements.txt

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

alembic/old_versions/20251108_nav_tops_soft_delete.py

@@ -0,0 +1,36 @@
+"""Update nav_tops unique constraint to include deleted_at"""
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '20251108_nav_tops_soft_delete'
+down_revision = '20251108_soft_delete_all'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    
+    # Drop existing constraint
+    op.drop_constraint('uq_nav_tops_label_slug', 'nav_tops', type_='unique')
+
+    # Add new constraint including deleted_at
+    op.create_unique_constraint(
+        'uq_nav_tops_label_slug',
+        'nav_tops',
+        ['label', 'slug', 'deleted_at']
+    )
+
+
+def downgrade():
+    # Drop new constraint
+    op.drop_constraint('uq_nav_tops_label_slug', 'nav_tops', type_='unique')
+
+    # Restore old constraint
+    op.create_unique_constraint(
+        'uq_nav_tops_label_slug',
+        'nav_tops',
+        ['label', 'slug']
+    )