feat: implement tool types definition system

- Add ToolType SQLAlchemy model with Docker Compose template support
- Create CRUD API endpoints for tool type management
- Implement YAML and template variable validation
- Add built-in tool types (code-server, jupyter-notebook) seeded on startup
- Create frontend page with list, create, edit, and delete functionality
- Add tool types navigation to app shell
- Update mypy config to ignore missing imports

Quality gates: ruff (passed), mypy (passed), pytest unit (8 passed),
typecheck (passed), lint (passed), build (passed)

apps/api/alembic/versions/0004_tool_types.py

@@ -0,0 +1,49 @@
+"""add tool_types table
+
+Revision ID: 0004_tool_types
+Revises: 0003_user_configs
+Create Date: 2026-05-18 15:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "0004_tool_types"
+down_revision: Union[str, None] = "0003_user_configs"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "tool_types",
+        sa.Column("id", sa.Uuid(as_uuid=True), primary_key=True),
+        sa.Column("name", sa.String(255), nullable=False, unique=True),
+        sa.Column("display_name", sa.String(255), nullable=False),
+        sa.Column("description", sa.Text(), nullable=True),
+        sa.Column("compose_template", sa.Text(), nullable=False),
+        sa.Column("required_variables", sa.JSON(), nullable=False, default=list),
+        sa.Column("is_builtin", sa.Boolean(), nullable=False, default=False),
+        sa.Column("created_by_id", sa.Uuid(as_uuid=True), sa.ForeignKey("users.id"), nullable=True),
+        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()"),
+            onupdate=sa.text("now()"),
+            nullable=False,
+        ),
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("tool_types")