changelog for 1.2.3

[SiteRelEnby]

Stamps the changelog for 1.2.3 and reconciles a filing error.

Changes

• [Unreleased] -> ## [1.2.3] - 2026-07-15, collapsed into Added / Fixed / Security (Keep a Changelog order).
• Moves the Display timezone and Relationships entries out of [1.2.2] and into 1.2.3. They were filed under [1.2.2] after that tag was cut, so they never actually shipped in 1.2.2; [1.2.2] is left with only the four fixes it really contained.
• No code changes; changelog only. versionCode/name come from the tag via CI.

Release

• Tag: v1.2.3 (signed), points at the changelog for 1.2.3 commit.
• versionCode 102030 (phone) / 102031 (wear), both > v1.2.2.
• Release variants build green; 168 tasks, app + wear unit tests pass.
• No backend dependency: Ampersand's endpoints are already live, everything else is client-side.