feat(todo): quick add suggests projects and labels as # and @ are typed (ADR 0033, D15)

Up to five projects or labels whose name, or a word of it, starts with
what follows the symbol show below the title; one tapped completes it.
None for a symbol inside a word (C#), nor once a name is typed whole.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

docs/adr/0033-halkyon-todo.md

@@ -220,7 +220,9 @@ alternative was put to them, the choice is theirs.
   `die`, `mit`) being everyday words. Quick add shows its title alone at first, its
   chips once typing starts, a chip picked taking its token out of the title, and the
   description and the deadline behind its + (the description also from the down
-  arrow).
+  arrow). As `#` or `@` is typed, up to five projects or labels whose name, or a word
+  of it, starts with what follows are offered below the title, one tapped completing
+  it; none for a symbol inside a word (`C#`), nor once a name is typed whole.
 - **D16 Dragging** (the developer's, 1 Nov, as Todoist's): a row of a project's list
   (the Inbox's too), held, is dragged into another place, a line showing where: the
   upper half of a row puts it before that row, the lower half after it, and the lower
@@ -235,8 +237,7 @@ alternative was put to them, the choice is theirs.
   next task below the one before); on a day in Upcoming, for that day; on Today, for
   today. Today's and Upcoming's rows aren't dragged, their order being their dates',
   times' and priorities'.
-- **To come**: suggestions of projects and labels as `#` and `@` are typed; dragging a
-  task onto another day in Upcoming.
+- **To come**: dragging a task onto another day in Upcoming.
 
 ## Steps