chore(release): 0.3.0

Closes the `Unreleased` section as `## [0.3.0] - 2026-08-24` and bumps the
workspace version, the two edits `ci/verify-version.sh` gates a release PR on:
the check fails the PR if `releases/v{version}` already exists on the build
host, so the bump is what makes the merge to `release` publishable.

The closed section carries a handful of items that shipped in `0.2.0` — the
Docker-daemon restart fix, per-user event-triage tuning, the file viewer's
syntax highlighting. CHANGELOG.md was written after that release and backfilled
them, and `0.2.0` has no section of its own to move them into, so they are
recorded here rather than nowhere.

CHANGELOG.md

@@ -8,6 +8,8 @@ release PR may merge — and a section is closed at the commit that bumps it.
 
 ## [Unreleased]
 
+## [0.3.0] - 2026-08-24
+
 ### Added
 
 - The assistant can now explain the **Dashboard** and the admin's **Roles** page: ask it