v0.6.1: pin Keep/Deleted folders to sidebar bottom; highlight All sources

- Move the Keep/Deleted system folders out of the scrolling source list into a
  pinned section at the bottom of the sidebar (only sources scroll now), so the
  folders stay reachable with many sources. Renamed .source-folders ->
  .system-folders; .source-list flexes to fill.
- "All sources" is visually distinct (bold + subtle blue tint) as the primary
  entry.

Template/CSS only. Feed/trash rendering tests pass; feed renders in all views.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -9,6 +9,15 @@ former name, "Daybook".)
 
 _Nothing yet._
 
+## [0.6.1] — 2026-09-07
+
+### Changed
+- Sidebar: the **Keep / Deleted folders are pinned to the bottom** — only the
+  source list scrolls, so the folders stay reachable no matter how many sources
+  you have. **"All sources"** is now visually distinct (bold + subtle blue tint)
+  as the primary entry. (Internal: `.source-folders` class renamed to
+  `.system-folders`.)
+
 ## [0.6.0] — 2026-09-07
 
 ### Added
@@ -205,7 +214,8 @@ First tagged release.
 - Dockerised (Gunicorn + whitenoise), SQLite, `git`-based deploy with a
   runbook (`deploy/cloud_agent_deploy.md`) and health check.
 
-[Unreleased]: https://git.cygnus.systems/peter/daybook/compare/v0.6.0...HEAD
+[Unreleased]: https://git.cygnus.systems/peter/daybook/compare/v0.6.1...HEAD
+[0.6.1]: https://git.cygnus.systems/peter/daybook/compare/v0.6.0...v0.6.1
 [0.6.0]: https://git.cygnus.systems/peter/daybook/compare/v0.5.1...v0.6.0
 [0.5.1]: https://git.cygnus.systems/peter/daybook/compare/v0.5.0...v0.5.1
 [0.5.0]: https://git.cygnus.systems/peter/daybook/compare/v0.4.1...v0.5.0