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/n4l2i8j0k1_drop_domain_events_table.py

@@ -0,0 +1,46 @@
+"""drop domain_events table
+
+Revision ID: n4l2i8j0k1
+Revises: m3k1h7i9j0
+Create Date: 2026-02-22
+
+The domain_events table is no longer used — all events now flow through
+ap_activities with the unified activity bus.
+"""
+
+revision = "n4l2i8j0k1"
+down_revision = "m3k1h7i9j0"
+branch_labels = None
+depends_on = None
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import JSONB
+
+
+def upgrade() -> None:
+    op.drop_index("ix_domain_events_state", table_name="domain_events")
+    op.drop_index("ix_domain_events_event_type", table_name="domain_events")
+    op.drop_table("domain_events")
+
+
+def downgrade() -> None:
+    op.create_table(
+        "domain_events",
+        sa.Column("id", sa.Integer(), primary_key=True, autoincrement=True),
+        sa.Column("event_type", sa.String(128), nullable=False),
+        sa.Column("aggregate_type", sa.String(64), nullable=False),
+        sa.Column("aggregate_id", sa.Integer(), nullable=False),
+        sa.Column("payload", JSONB(), nullable=True),
+        sa.Column("state", sa.String(20), nullable=False, server_default="pending"),
+        sa.Column("attempts", sa.Integer(), nullable=False, server_default="0"),
+        sa.Column("max_attempts", sa.Integer(), nullable=False, server_default="5"),
+        sa.Column("last_error", sa.Text(), nullable=True),
+        sa.Column(
+            "created_at", sa.DateTime(timezone=True),
+            nullable=False, server_default=sa.func.now(),
+        ),
+        sa.Column("processed_at", sa.DateTime(timezone=True), nullable=True),
+    )
+    op.create_index("ix_domain_events_event_type", "domain_events", ["event_type"])
+    op.create_index("ix_domain_events_state", "domain_events", ["state"])