Fold [Unreleased] into [3.5.0] for the release

[erikdarlingdata]

Release prep. The 16 [Unreleased] entries move section-for-section into the existing ## [3.5.0] - 2026-08-19 block (5 Added, 3 Changed, 8 Fixed), newest first.

Mechanical and verified rather than eyeballed: the fold script asserts the moved entry count matches what it removed and that the file's total bullet count is unchanged (919 → 919), and it edits on bytes so the file's CRLF line endings survive. Docs-only, so the version-bump gate skips it.

[claude]

Reviewed. This is a docs-only CHANGELOG.md reorganization with no code changes, so the T-SQL style conventions and Lite/Darling parity checks don't apply here.

Verified the fold mechanically against origin/dev:

• All 5 Added / 3 Changed / 8 Fixed [Unreleased] entries land under ## [3.5.0] - 2026-08-19, newest-first, with no loss or duplication (including Database/LastEventUtc on the incident projection, which stayed in place since it sat directly under the renamed heading and needed no diff hunk).
• Single ## [3.5.0] heading, one each of Added/Changed/Fixed, correct splice points with blank-line separation intact.
• Bullet count unchanged (920 → 920 by my count, consistent with the PR's own 919 → 919 assertion either way).
• CRLF line endings preserved throughout.
• Issue link references at the bottom of the file are untouched and still resolve.

No issues found. LGTM.