feat(api): multi-project folder manifest for daily brief

Add build_brief_multi_project_manifest() to deep_agent.py that fetches
all project folder manifests via execute_on_client and keeps the top 5
most-recently-modified files per project. Wire into run_home_brief in
brief_agent.py, injecting the <linked_folders> block into the system
prompt alongside FOLDER_TOOLS.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/core/brief_agent.py

@@ -21,6 +21,7 @@ from app.core.deep_agent import (
     _relational_memory_injection,
     _run_single_agent_stream,
     _trace_id_from_context,
+    build_brief_multi_project_manifest,
 )
 from app.core.langfuse_client import compile_prompt, get_prompt_or_fallback
 
@@ -159,6 +160,8 @@ async def run_home_brief(
     Yields (event_type, data) tuples identical to _run_single_agent_stream.
     Do NOT post-process output through _normalize_tagged_list_lines.
     """
+    from app.agents.folder_agent import FOLDER_TOOLS
+
     trace_id = _trace_id_from_context(context)
     today = date.today().isoformat()
     language = _resolve_language(context)
@@ -171,7 +174,10 @@ async def run_home_brief(
     if today not in system_prompt:
         system_prompt += f"\nToday is {today}."
 
-    tools = _build_read_tools(user_id, trace_id)
+    brief_manifest = await build_brief_multi_project_manifest()
+    system_prompt = system_prompt + ("\n\n" + brief_manifest if brief_manifest else "")
+
+    tools = [*_build_read_tools(user_id, trace_id), *FOLDER_TOOLS]
     async for event in _run_single_agent_stream(
         user_id=user_id,
         system_prompt=system_prompt,

app/core/deep_agent.py

@@ -110,6 +110,35 @@ async def _fetch_project_manifest(project_id: str) -> dict | None:
         return None
 
 
+async def build_brief_multi_project_manifest() -> str:
+    """Build a compact multi-project manifest for the daily brief agent.
+
+    Calls execute_on_client('list_projects_with_folder_manifests') and keeps
+    the top 5 most-recently-modified files per project.
+    """
+    try:
+        result = await execute_on_client(
+            action="list_projects_with_folder_manifests",
+            data={},
+        )
+    except Exception:
+        return ""
+    projects = (result or {}).get("projects") or []
+    if not projects:
+        return ""
+    blocks: list[str] = ["<linked_folders>"]
+    for p in projects:
+        files = sorted(p.get("files", []), key=lambda f: f.get("mtimeMs", 0), reverse=True)[:5]
+        if not files:
+            continue
+        blocks.append(f"project: {p.get('projectName','?')} [{p.get('projectId','?')}]")
+        blocks.append(f"  path: {p.get('folderPath','?')}  (scanned {p.get('lastScannedAt','?')})")
+        for f in files:
+            blocks.append(f"  - /{f['relPath']}  [{f.get('kind','text')}]  {f.get('summary','')}")
+    blocks.append("</linked_folders>")
+    return "\n".join(blocks)
+
+
 def _datetime_context_injection(context: dict[str, Any]) -> str:
     """Build a comprehensive DATE CONTEXT block with pre-computed ms-epoch boundaries for common ranges."""
     fp = context.get("format_prefs")