feat(notes): add_note MCP tool with a per-day agent cap

Agents can write into the user's daily notes, but only within limits:
max 10 agent notes a day, max 500 characters, add only — no edit, no
delete. A new from_agent column separates their lines from the user's
so the cap counts the right ones and the UI can mark them.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/ClaudeDo.Ui/Services/ReportDtos.cs

@@ -1,3 +1,3 @@
 namespace ClaudeDo.Ui.Services;
 
-public sealed record DailyNoteDto(string Id, string Date, string Text, int SortOrder);
+public sealed record DailyNoteDto(string Id, string Date, string Text, int SortOrder, bool FromAgent);