feat: add missing features from main merge

1. Built-in tool type seeding (apps/api/src/seeds/builtin_tool_types.py):
   - Seeds code-server, jupyter-notebook, and opencode on startup.
   - Adapts to current dev model: uses interface_type (single string)
     instead of interfaces array, and created_by_id=None instead of
     is_builtin flag.
   - Called from main.py startup event.

2. Config profile default management:
   - Adds default_profile_id and default_profiles properties to
     UserConfig model for JSON-backed per-tool-type defaults.
   - Adds GET /config-profiles/defaults, PUT /config-profiles/defaults,
     and GET /config-profiles/defaults/{tool_type_id} endpoints.
   - Validates that all profile IDs in default mappings belong to the
     authenticated user before persisting.

3. Config profile unique constraint:
   - Adds __table_args__ with UniqueConstraint(user_id, name) to
     ConfigProfile model. The constraint already exists in the DB
     from migration 2026_05_24_add_config_profiles.py; this just
     aligns the SQLAlchemy model with the schema.

Quality gates: py_compile passed, ruff passed on all modified files.

apps/api/src/models/config_profile.py

@@ -1,7 +1,15 @@
 import uuid
 from typing import TYPE_CHECKING
 
-from sqlalchemy import ForeignKey, JSON, Integer, String, Text, Boolean
+from sqlalchemy import (
+    Boolean,
+    ForeignKey,
+    JSON,
+    Integer,
+    String,
+    Text,
+    UniqueConstraint,
+)
 from sqlalchemy import Uuid as UUID
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
@@ -15,6 +23,9 @@ if TYPE_CHECKING:
 
 class ConfigProfile(UUIDPrimaryKeyMixin, TimestampMixin, Base):
     __tablename__ = "config_profiles"
+    __table_args__ = (
+        UniqueConstraint("user_id", "name", name="uq_config_profiles_user_name"),
+    )
 
     user_id: Mapped[uuid.UUID] = mapped_column(
         UUID(), ForeignKey("users.id", ondelete="CASCADE"), nullable=False

apps/api/src/models/user_config.py

@@ -1,8 +1,8 @@
 import uuid
 from typing import TYPE_CHECKING
 
-from sqlalchemy import ForeignKey
-from sqlalchemy import JSON, Uuid as UUID
+from sqlalchemy import ForeignKey, JSON
+from sqlalchemy import Uuid as UUID
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from src.models.base import Base, TimestampMixin, UUIDPrimaryKeyMixin
@@ -18,3 +18,30 @@ class UserConfig(UUIDPrimaryKeyMixin, TimestampMixin, Base):
     config: Mapped[dict[str, object]] = mapped_column(JSON, default=dict, nullable=False)
 
     user: Mapped["User"] = relationship(back_populates="user_config")
+
+    @property
+    def default_profile_id(self) -> uuid.UUID | None:
+        """Return the legacy global default profile ID from config JSON."""
+        profile_id = self.config.get("default_profile_id")
+        if isinstance(profile_id, str):
+            return uuid.UUID(profile_id)
+        return None
+
+    @default_profile_id.setter
+    def default_profile_id(self, value: uuid.UUID | None) -> None:
+        if value is not None:
+            self.config["default_profile_id"] = str(value)
+        elif "default_profile_id" in self.config:
+            del self.config["default_profile_id"]
+
+    @property
+    def default_profiles(self) -> dict[str, str]:
+        """Return per-tool-type default profile IDs from config JSON."""
+        value = self.config.get("default_profiles", {})
+        if isinstance(value, dict):
+            return {str(k): str(v) for k, v in value.items()}
+        return {}
+
+    @default_profiles.setter
+    def default_profiles(self, value: dict[str, str]) -> None:
+        self.config["default_profiles"] = value