feat(opencode-web-terminal): complete OpenCode web terminal implementation

- Update OpenCode compose template with web server on port 3000
- Add default_port=3000 and interfaces=[terminal, web] to OpenCode seed data
- Remove hardcoded 8080 fallback in tunnel creation
- Fail gracefully when tool type has no default_port configured
- Update frontend ToolType API to include default_port, category, interfaces
- Add port, category, and interfaces fields to tool type creation form
- Display port and interfaces in tool type cards
- Create migration 0012 to make default_port non-nullable
- Set default_port values for existing built-in tool types
- Quality gates: typecheck ✓, build ✓, Python syntax ✓

apps/api/alembic/versions/0012_tool_type_default_port_not_null.py

@@ -0,0 +1,48 @@
+"""make default_port non-nullable and set values
+
+Revision ID: 0012_tool_type_default_port_not_null
+Revises: 0011_tool_instance_tunnel_fields
+Create Date: 2026-05-20 15:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = "0012_tool_type_default_port_not_null"
+down_revision: Union[str, None] = "0011_tool_instance_tunnel_fields"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Set default_port for existing built-in tool types
+    op.execute("""
+        UPDATE tool_types 
+        SET default_port = CASE 
+            WHEN name = 'code-server' THEN 8443
+            WHEN name = 'jupyter-notebook' THEN 8888
+            WHEN name = 'opencode' THEN 3000
+            ELSE 8080
+        END
+        WHERE default_port IS NULL
+    """)
+    
+    # Make default_port non-nullable
+    op.alter_column(
+        "tool_types",
+        "default_port",
+        existing_type=sa.Integer(),
+        nullable=False,
+    )
+
+
+def downgrade() -> None:
+    op.alter_column(
+        "tool_types",
+        "default_port",
+        existing_type=sa.Integer(),
+        nullable=True,
+    )