docs: cut jump-to-date (M2) from V1 scope

The date-picker half of M2 is dropped entirely; the "Today" half already
shipped in v0.5. V1 is now feature-complete and only a polish/QA pass
remains before v1.0.

Updated the living planning docs (ROADMAP, STATE, REQUIREMENTS) and the
design spec; corrected the v0.5.0 CHANGELOG note that promised M2 would
return in v1.0.

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

CHANGELOG.md

@@ -16,7 +16,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   separate from the system VISIBLE flag) and applied centrally in the
   repository, so month/week/day re-filter live the moment a switch flips.
   The drawer was trimmed to just Today, the calendar filter, and Settings
-  (the stubbed jump-to-date entry was removed; M2 returns in v1.0)
+  (the stubbed jump-to-date entry was removed; jump-to-date was later cut
+  from scope entirely)
 - Settings (M4): a full-screen destination with
   - **Appearance** — theme (System / Light / Dark), Material You dynamic colour
     (auto-disabled below Android 12), week start (Automatic / Monday / Sunday)