Fold the custom-alert follow-ups (tag scope, range operators, last-fired) into the changelog

[erikdarlingdata]

Documentation only. Consolidated update to the #3285 [Unreleased] Added bullet now that the three follow-up slices shipped (one post-wave splice per the changelog batching rule):

• Tag scope (Custom alerts: tag scope (scope.mode: "tag") #3350 / Add tag scope to custom alert rules (#3350) #3366) → "a scope of all servers, a chosen few, or a fleet tag".
• between/outside range operators (Custom alerts: between / outside range predicate operators #3351 / Add between/outside range predicate operators for custom alert rules (#3351) #3371) → "a comparison with Warning/Critical thresholds or a range (within or outside a band)".
• Last-fired on rule cards (Custom alerts: show last-fired time on rule cards #3360 / Show each custom-alert rule's last-fired time on the rule cards (#3360) #3370) → "the rule list shows when each rule last fired".

Byte-precise edit, CRLF preserved (3677 → 3677, 0 bare CR), one line changed.

🤖 Generated with Claude Code

https://claude.ai/code/session_01WejwpgWF5Xfm3fAmoEbFz4

[claude]

Reviewed. This is a documentation-only edit (1 line changed in CHANGELOG.md, no code) that folds three follow-up features into the existing #3285 Added bullet in [Unreleased].

Verified:

• Accuracy: the new clauses ("or a range (within or outside a band)", "a chosen few, or a fleet tag", "the rule list shows when each rule last fired") match the actual shipped behavior in the referenced merged PRs (Add tag scope to custom alert rules (#3350) #3366 tag scope, Add between/outside range predicate operators for custom alert rules (#3351) #3371 between/outside range operators, Show each custom-alert rule's last-fired time on the rule cards (#3360) #3370 last-fired on rule cards).
• CRLF/line-count claim: confirmed — file is still CRLF-terminated, still 3677 lines, and git diff shows exactly one line changed.
• Convention: amending the still-[Unreleased] bullet as follow-up slices land (rather than adding new bullets) matches how other multi-PR features are handled elsewhere in this changelog.

No correctness, parity, security, or performance concerns — there's no code in this diff to affect Lite/Darling parity. Nothing to flag.