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/prompts.py

@@ -342,3 +342,24 @@ JSON_ACTION_FALLBACK_PROMPT = """你当前运行在 JSON action fallback 模式
 6. 只能使用系统消息里明确列出的工具名。
 7. `arguments` 必须是 JSON 对象。
 """
+
+
+TOP_LEVEL_SYSTEM_PROMPTS_BY_KEY = {
+    "master": MASTER_SYSTEM_PROMPT,
+    "schedule_planner": SCHEDULE_PLANNER_SYSTEM_PROMPT,
+    "executor": EXECUTOR_SYSTEM_PROMPT,
+    "librarian": LIBRARIAN_SYSTEM_PROMPT,
+    "analyst": ANALYST_SYSTEM_PROMPT,
+}
+
+
+SUB_COMMANDER_PROMPTS_BY_KEY = {
+    "schedule_analysis": SCHEDULE_ANALYSIS_PROMPT,
+    "schedule_planning": SCHEDULE_PLANNING_PROMPT,
+    "executor_tasks": EXECUTOR_TASKS_PROMPT,
+    "executor_forum": EXECUTOR_FORUM_PROMPT,
+    "librarian_retrieval": LIBRARIAN_RETRIEVAL_PROMPT,
+    "librarian_graph": LIBRARIAN_GRAPH_PROMPT,
+    "analyst_progress": ANALYST_PROGRESS_PROMPT,
+    "analyst_insights": ANALYST_INSIGHTS_PROMPT,
+}