Monorepo: consolidate 7 repos into one

Combines shared, blog, market, cart, events, federation, and account
into a single repository. Eliminates submodule sync, sibling model
copying at build time, and per-app CI orchestration.

Changes:
- Remove per-app .git, .gitmodules, .gitea, submodule shared/ dirs
- Remove stale sibling model copies from each app
- Update all 6 Dockerfiles for monorepo build context (root = .)
- Add build directives to docker-compose.yml
- Add single .gitea/workflows/ci.yml with change detection
- Add .dockerignore for monorepo build context
- Create __init__.py for federation and account (cross-app imports)

shared/alembic/versions/a9f54e4eaf02_add_menu_items_table.py

@@ -0,0 +1,37 @@
+
+# Alembic migration script template
+
+"""add menu_items table
+
+Revision ID: a9f54e4eaf02
+Revises: 6cb124491c9d
+Create Date: 2025-12-07 17:38:54.839296
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision = 'a9f54e4eaf02'
+down_revision = '6cb124491c9d'
+branch_labels = None
+depends_on = None
+
+def upgrade() -> None:
+    op.create_table('menu_items',
+        sa.Column('id', sa.Integer(), autoincrement=True, nullable=False),
+        sa.Column('post_id', sa.Integer(), nullable=False),
+        sa.Column('sort_order', sa.Integer(), nullable=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
+        sa.Column('deleted_at', sa.DateTime(timezone=True), nullable=True),
+        sa.ForeignKeyConstraint(['post_id'], ['posts.id'], ondelete='CASCADE'),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_menu_items_post_id'), 'menu_items', ['post_id'], unique=False)
+    op.create_index(op.f('ix_menu_items_sort_order'), 'menu_items', ['sort_order'], unique=False)
+
+def downgrade() -> None:
+    op.drop_index(op.f('ix_menu_items_sort_order'), table_name='menu_items')
+    op.drop_index(op.f('ix_menu_items_post_id'), table_name='menu_items')
+    op.drop_table('menu_items')