feat: add agent registry manifests and coverage

Introduce a manifest-backed agent registry surface and align graph tests with the new runtime prompt and tool indexing behavior.

backend/app/agents/registry/validator.py

@@ -0,0 +1,55 @@
+from collections.abc import Iterable
+
+from app.agents.registry.models import (
+    AgentManifest,
+    CapabilityManifest,
+    SpecialistTemplateManifest,
+    SubCommanderManifest,
+)
+
+
+def _validate_unique_ids(values: Iterable[str], label: str) -> set[str]:
+    unique_values: set[str] = set()
+    for value in values:
+        if value in unique_values:
+            raise ValueError(f"duplicate {label}: {value}")
+        unique_values.add(value)
+    return unique_values
+
+
+def validate_registry_bundle(
+    *,
+    agents: list[AgentManifest],
+    sub_commanders: list[SubCommanderManifest],
+    capabilities: list[CapabilityManifest],
+    specialist_templates: list[SpecialistTemplateManifest],
+) -> None:
+    agent_ids = _validate_unique_ids((agent.agent_id for agent in agents), "agent id")
+    _validate_unique_ids(
+        (sub_commander.sub_commander_id for sub_commander in sub_commanders),
+        "sub commander id",
+    )
+    capability_ids = _validate_unique_ids(
+        (capability.capability_id for capability in capabilities),
+        "capability id",
+    )
+    _validate_unique_ids(
+        (specialist_template.template_id for specialist_template in specialist_templates),
+        "template id",
+    )
+
+    for sub_commander in sub_commanders:
+        if sub_commander.parent_agent_id not in agent_ids:
+            raise ValueError(f"unknown parent agent id: {sub_commander.parent_agent_id}")
+
+        for capability_id in sub_commander.capability_ids:
+            if capability_id not in capability_ids:
+                raise ValueError(f"unknown capability id: {capability_id}")
+
+    for specialist_template in specialist_templates:
+        if specialist_template.allowed_capability_ids is None:
+            continue
+
+        for capability_id in specialist_template.allowed_capability_ids:
+            if capability_id not in capability_ids:
+                raise ValueError(f"unknown capability id: {capability_id}")