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/indexes.py

@@ -0,0 +1,76 @@
+from __future__ import annotations
+
+from collections.abc import Mapping
+from dataclasses import dataclass
+from types import MappingProxyType
+
+from app.agents.registry.loader import RegistryBundle
+from app.agents.registry.models import (
+    AgentManifest,
+    CapabilityManifest,
+    SpecialistTemplateManifest,
+    SubCommanderManifest,
+)
+
+
+@dataclass(frozen=True)
+class RegistryIndexes:
+    agent_by_id: Mapping[str, AgentManifest]
+    sub_commander_by_id: Mapping[str, SubCommanderManifest]
+    capability_by_id: Mapping[str, CapabilityManifest]
+    specialist_template_by_id: Mapping[str, SpecialistTemplateManifest]
+    agent_prompt_key_by_id: Mapping[str, str]
+    sub_commander_prompt_key_by_id: Mapping[str, str]
+    skill_context_key_by_agent_id: Mapping[str, str]
+    capability_id_by_tool_name: Mapping[str, str]
+    capability_ids_by_sub_commander_id: Mapping[str, tuple[str, ...]]
+
+
+def summarize_registry_indexes(indexes: RegistryIndexes) -> dict[str, int]:
+    return {
+        "agent_count": len(indexes.agent_by_id),
+        "sub_commander_count": len(indexes.sub_commander_by_id),
+        "capability_count": len(indexes.capability_by_id),
+        "specialist_template_count": len(indexes.specialist_template_by_id),
+    }
+
+
+def build_registry_indexes(bundle: RegistryBundle) -> RegistryIndexes:
+    agent_by_id = {agent.agent_id: agent for agent in bundle.agents}
+    sub_commander_by_id = {
+        sub_commander.sub_commander_id: sub_commander
+        for sub_commander in bundle.sub_commanders
+    }
+    capability_by_id = {
+        capability.capability_id: capability for capability in bundle.capabilities
+    }
+    specialist_template_by_id = {
+        template.template_id: template for template in bundle.specialist_templates
+    }
+
+    return RegistryIndexes(
+        agent_by_id=MappingProxyType(agent_by_id),
+        sub_commander_by_id=MappingProxyType(sub_commander_by_id),
+        capability_by_id=MappingProxyType(capability_by_id),
+        specialist_template_by_id=MappingProxyType(specialist_template_by_id),
+        agent_prompt_key_by_id=MappingProxyType({
+            agent.agent_id: agent.system_prompt_key for agent in bundle.agents
+        }),
+        sub_commander_prompt_key_by_id=MappingProxyType({
+            sub_commander.sub_commander_id: sub_commander.sub_commander_id
+            for sub_commander in bundle.sub_commanders
+        }),
+        skill_context_key_by_agent_id=MappingProxyType({
+            agent.agent_id: agent.skill_context_key
+            for agent in bundle.agents
+            if agent.skill_context_key is not None
+        }),
+        capability_id_by_tool_name=MappingProxyType({
+            capability.tool_name: capability.capability_id
+            for capability in bundle.capabilities
+        }),
+        capability_ids_by_sub_commander_id=MappingProxyType({
+            sub_commander.sub_commander_id: tuple(sub_commander.capability_ids)
+            for sub_commander in bundle.sub_commanders
+        }),
+    )