Matrix intake: main-timeline nudge, clearer messages, note text in grid

Four bot-side UX fixes surfaced by the live smoke:
- Post a brief pointer in the main timeline (a reply to the user's message)
  alongside the in-thread proposal card, so proposals aren't missed inside a
  thread. Pointer only — approvals still happen in the thread, where the note
  is visible (you can't make an informed yes/no without seeing it).
- A bare yes/no typed in the main timeline while a proposal is pending now
  gets a "reply in the thread" redirect instead of "couldn't tell what to record."
- Clearer commit confirmations: "Created a new grid entry for X" vs
  "Logged a note on X (existing grid entry)."
- Send a blank communication subject when a note is present so the grid's
  one-line note summary shows the note text, not the "(Matrix)" label
  (provenance stays in source="matrix_intake").

backend/matrix_intake/crm_client.py

@@ -97,11 +97,16 @@ def build_commit_payload(proposal):
         "title": proposal.get("contact_title") or "",
     }
     note = proposal.get("note") or ""
+    # The CRM's grid note line uses subject-or-body for its one-line summary, so a non-empty
+    # subject hides the actual note text. Send a blank subject when there's a note (let the note
+    # itself show in the grid); fall back to a provenance label only when there's nothing to
+    # show. Provenance is recorded via source="matrix_intake" either way.
+    intent_label = "Note (Matrix)" if proposal.get("intent") == "meeting_note" else "Intake (Matrix)"
     payload = {
         "contact": contact,
         "type": "note",
         "body": note,
-        "subject": "Intake (Matrix)" if proposal.get("intent") != "meeting_note" else "Note (Matrix)",
+        "subject": "" if note.strip() else intent_label,
         "append_note": True,
         "source": "matrix_intake",
     }
@@ -123,5 +128,5 @@ def commit(proposal):
     row = (data.get("data") or {}).get("row") or {}
     name = row.get("investor_name") or payload.get("investor_name") or "investor"
     if proposal.get("_match_id"):
-        return f"Logged note to **{name}**."
-    return f"Added **{name}** to the grid" + (" with a note." if payload.get("body") else ".")
+        return f"Logged a note on **{name}** (existing grid entry)."
+    return f"Created a new grid entry for **{name}**" + (" and logged a note." if payload.get("body") else ".")