feat: agent versioning and model configurations override (#227)

* feat: add tests and migrations

* feat: workflow versioning among published and draft

* feat: add a new settings page to simplify workflow detail page

* fix: fix tsclient generation

api/services/configuration/resolve.py

@@ -0,0 +1,83 @@
+"""Resolve effective config by merging per-workflow model overrides onto global config."""
+
+from __future__ import annotations
+
+from api.schemas.user_configuration import UserConfiguration
+from api.services.configuration.registry import (
+    REGISTRY,
+    ServiceType,
+)
+
+# Maps override key → (UserConfiguration field, ServiceType for registry lookup)
+_SECTION_MAP: dict[str, ServiceType] = {
+    "llm": ServiceType.LLM,
+    "tts": ServiceType.TTS,
+    "stt": ServiceType.STT,
+    "realtime": ServiceType.REALTIME,
+}
+
+
+def _build_section_from_override(service_type: ServiceType, override: dict):
+    """Construct a typed config object from a raw override dict using the registry."""
+    provider = override.get("provider")
+    if not provider:
+        return None
+    registry = REGISTRY.get(service_type, {})
+    config_cls = registry.get(provider)
+    if config_cls is None:
+        return None
+    return config_cls(**override)
+
+
+def resolve_effective_config(
+    user_config: UserConfiguration,
+    model_overrides: dict | None,
+) -> UserConfiguration:
+    """Deep-merge workflow model_overrides onto global user config.
+
+    - If model_overrides is None or empty, returns a copy of user_config unchanged.
+    - For each section (llm, tts, stt, realtime), if the override contains that key:
+      - If the global section is None, construct a new config from the override.
+      - If the provider changes, construct a new config from the override.
+      - Otherwise, merge override fields onto the existing config (model_copy).
+    - is_realtime is a simple boolean override.
+    - Sections not in the override are inherited from global unchanged.
+    - The original user_config is never mutated.
+    """
+    if not model_overrides:
+        return user_config.model_copy(deep=True)
+
+    effective = user_config.model_copy(deep=True)
+
+    # Handle is_realtime boolean
+    if "is_realtime" in model_overrides:
+        effective.is_realtime = model_overrides["is_realtime"]
+
+    # Handle service sections
+    for section_key, service_type in _SECTION_MAP.items():
+        if section_key not in model_overrides:
+            continue
+
+        override = model_overrides[section_key]
+        base = getattr(effective, section_key)
+
+        if base is None:
+            # No global config for this section — build from override
+            setattr(
+                effective,
+                section_key,
+                _build_section_from_override(service_type, override),
+            )
+        elif "provider" in override and override["provider"] != base.provider:
+            # Provider changed — must construct new typed object
+            setattr(
+                effective,
+                section_key,
+                _build_section_from_override(service_type, override),
+            )
+        else:
+            # Same provider — merge fields onto existing config
+            merged = base.model_copy(update=override)
+            setattr(effective, section_key, merged)
+
+    return effective