Merge branch 'feat/tool-definition-manifest' into dev

Conflicts resolved:
- models/__init__.py: kept both TerminalSessionModel (from dev) and
  ToolDefinitionManifest (from feature branch)
- alembic migration: kept full migration (already applied to DB)
- openspec/config.yaml: kept full config with SDD settings

apps/api/src/models/__init__.py

@@ -4,6 +4,7 @@ from src.models.config_profile import ConfigProfile, ConfigProfileInclude
 from src.models.git_repository import GitRepository
 from src.models.project import Project
 from src.models.ssh_key import SSHKey
+from src.models.terminal_session import TerminalSessionModel
 from src.models.tool_definition_manifest import ToolDefinitionManifest
 from src.models.tool_instance import ToolInstance
 from src.models.tool_type import ToolType
@@ -18,6 +19,7 @@ __all__ = [
     "GitRepository",
     "Project",
     "SSHKey",
+    "TerminalSessionModel",
     "ToolDefinitionManifest",
     "ToolInstance",
     "ToolType",