rate limit: domain ceiling for all IPs, trusted app override

Invert level-2 semantics so domain limits apply to every client IP and
application limits with trusted IPs raise the ceiling above the domain
(still capped by level 1). Panel shows L1, validates maxima, and documents
the model on Settings.

Co-authored-by: Cursor <cursoragent@cursor.com>

CHANGELOG.md

@@ -5,6 +5,22 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
 
 ## [Unreleased]
 
+### Changed
+
+- rate limiting (level 2): domain ceilings apply to every client IP (no IP
+  allowlist). An application ceiling with trusted IPs is an override
+  **above** the domain limit (still ≤ level 1) and skips the domain check for
+  those IPs; without IPs the application override is inactive. When no domain
+  ceiling is set, non-privileged senders use level 1 only. The panel shows the
+  level-1 backstop on domain/application forms and Settings, rejects maxima
+  above level 1, and requires an application override to exceed the domain
+  maximum. Operator guide and architecture updated.
+
+### Fixed
+
+- panel: on the domain DNS status grid, the Type (TXT) field height matches
+  the Host fields.
+
 ## [1.2.3] - 2026-08-12
 
 Domain detail layout and panel polish after 1.2.2. Upgrading is a tag bump; no