feat: extract shared infrastructure from shared_lib

Phase 1-3 of decoupling plan:
- Shared DB, models, infrastructure, browser, config, utils
- Event infrastructure (domain_events outbox, bus, processor)
- Structured logging
- Generic container concept (container_type/container_id)
- Alembic migrations for all schema changes

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

alembic/versions/0006_update_calendar_entries.py

@@ -0,0 +1,28 @@
+from alembic import op
+import sqlalchemy as sa
+
+revision = '0006_update_calendar_entries'
+down_revision = '0005_add_description'  # use the appropriate previous revision ID
+branch_labels = None
+depends_on = None
+
+def upgrade():
+    # Add user_id and session_id columns
+    op.add_column('calendar_entries', sa.Column('user_id', sa.Integer(), nullable=True))
+    op.create_foreign_key('fk_calendar_entries_user_id', 'calendar_entries', 'users', ['user_id'], ['id'])
+    op.add_column('calendar_entries', sa.Column('session_id', sa.String(length=128), nullable=True))
+    # Add state and cost columns
+    op.add_column('calendar_entries', sa.Column('state', sa.String(length=20), nullable=False, server_default='pending'))
+    op.add_column('calendar_entries', sa.Column('cost', sa.Numeric(10,2), nullable=False, server_default='10'))
+    # (Optional) Create indexes on the new columns
+    op.create_index('ix_calendar_entries_user_id', 'calendar_entries', ['user_id'])
+    op.create_index('ix_calendar_entries_session_id', 'calendar_entries', ['session_id'])
+
+def downgrade():
+    op.drop_index('ix_calendar_entries_session_id', table_name='calendar_entries')
+    op.drop_index('ix_calendar_entries_user_id', table_name='calendar_entries')
+    op.drop_column('calendar_entries', 'cost')
+    op.drop_column('calendar_entries', 'state')
+    op.drop_column('calendar_entries', 'session_id')
+    op.drop_constraint('fk_calendar_entries_user_id', 'calendar_entries', type_='foreignkey')
+    op.drop_column('calendar_entries', 'user_id')