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/20251107_123000_widen_alembic_version.py

@@ -0,0 +1,44 @@
+"""widen alembic_version.version_num to 255
+
+Revision ID: 20251107_123000_widen_alembic_version
+Revises: 20251107_121500_labels_stickers
+Create Date: 2025-11-07T12:30:00.000000
+"""
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision = "20251107_123000_widen_alembic_version"
+down_revision = "20251107_121500_labels_stickers"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    """Increase the size of alembic_version.version_num to 255."""
+
+    # Most projects use Postgres; this raw SQL is explicit and works reliably.
+    # Widening requires no USING clause on Postgres, but we'll be explicit for clarity.
+    op.execute(
+        "ALTER TABLE alembic_version "
+        "ALTER COLUMN version_num TYPE VARCHAR(255)"
+    )
+
+    # If you need cross-dialect support later, you could add dialect checks
+    # and use batch_alter_table for SQLite. For your Postgres setup, this is sufficient.
+
+
+def downgrade() -> None:
+    """Shrink alembic_version.version_num back to 32.
+
+    On Postgres, shrinking can fail if any row exceeds 32 chars.
+    We proactively truncate to 32 to guarantee a clean downgrade.
+    """
+    # Truncate any too-long values to fit back into VARCHAR(32)
+    op.execute(
+        "UPDATE alembic_version SET version_num = LEFT(version_num, 32)"
+    )
+    op.execute(
+        "ALTER TABLE alembic_version "
+        "ALTER COLUMN version_num TYPE VARCHAR(32)"
+    )