style: drop em-dashes from the prose added in this branch

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.changeset/history-list-and-past-session-search.md

@@ -4,14 +4,14 @@
 
 Home screen: make the past-conversation list usable, and let search find past sessions.
 
-- **#260** — "Resume Conversation" showed 4 rows and then dumped every remaining
+- **#260**: "Resume Conversation" showed 4 rows and then dumped every remaining
   one into a fixed 240px box, with no ordering or filtering. The list now opens
   with 10 rows, "Show more"/"Show less" grows and shrinks the box itself (the
   height cap is class-driven instead of fixed), and the header carries a filter
   box (matches name, folder, `#case` label and the conversation's prompts), a
   sort control (recent / name A–Z / folder A–Z, pinned rows still first) and a
   shown-of-total count. Filtering implies expansion, so every match is visible.
-- **#261** — the search box could not match a past project by folder name: its
+- **#261**: the search box could not match a past project by folder name: its
   session corpus was the live in-memory map, while past sessions come from
   `/api/sessions/unified`. Search now also harvests a bounded snapshot of that
   unified list, refreshed OUTSIDE the request path (published by