v0.7.1: in-app password change, custom labels, always-on folders

- Settings -> Account: change your own password (current + new), session
  preserved via update_session_auth_hash.
- Custom labels: per-user palette in Settings -> Labels; apply/remove from a
  message's ... menu (menu stays open, checkmark = applied). Labels are unified
  with tags; chip colours sync to the global TagColor. New Label model +
  migration 0017; POST /a/{id}/label (session, owner-scoped, palette-validated).
- Sidebar Keep/Deleted folders are now always shown; count badge only when
  non-empty. Updates the stale 'hide when empty' note in CLAUDE.md.

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

CHANGELOG.md

@@ -9,6 +9,24 @@ former name, "Daybook".)
 
 _Nothing yet._
 
+## [0.7.1] — 2026-09-08
+
+### Added
+- **Custom labels.** Curate a personal palette of coloured labels in
+  **Settings → Labels**, then apply them to any message from its ⋯ menu (or
+  right-click) — the menu stays open so you can apply several at once, with a
+  checkmark showing which are applied. Labels are unified with tags: applying
+  one adds it to the message's tags and renders as a chip. Backed by
+  `POST /a/{id}/label` (session-auth, owner-scoped, palette-validated); chip
+  colours sync to the global `TagColor`.
+- **Change your password in-app** from **Settings → Account**: enter the current
+  password, then a new one. Uses Django's `PasswordChangeForm` and keeps the
+  session logged in after the change.
+
+### Changed
+- Sidebar: the **Keep** and **Deleted** folders are now always shown (even when
+  empty); the count badge only appears when the folder is non-empty.
+
 ## [0.7.0] — 2026-09-07
 
 ### Added