release: 2.5.4: audit stage 4 - panel behaviour

Cut without asking, as the owner said on 2026-10-15.

Signing in costs the same for an unknown name (M8) and ends the session the
browser presented (L16); the Account password check has its own limit
(L15). The HTTP server bounds the request, the answer and idle connections;
the full backup moves its own deadline (L14). Monitoring refreshes are
scheduled from htmx:afterRequest with a back-off and a 30 s timeout, and a
lost session sends htmx to sign-in (M11). The Outbound log clamps its page
(L10) and filters by status and day; the multiplier refuses NaN (L11); a
rate-limited refusal is red (L18); Recalculate asks before it drops an
unsaved edit (L19); Reload configuration writes what a restore writes and
removes the keys of deleted domains (L13, L17). The cards layout orders by
number. A notification is owed to each recipient (migration 0011). A DNS
outage is unknown, each resolver with its own time (M14, M15). DMARC
reports too large are refused for their size. An inbound upstream has one
TLS mode, changed for all its domains (L5). Plus the findings of both
reviews (eaa7de0). Commits 07be0cf, 643892a, ca876c1, 80e3979, 2b8e0c0,
b90a2f0, eee089a, 006bed7, 32dfe4a, eaa7de0.

Rolled out to the test server as 2.5.3-post.eaa7de0 (the same code):
migration 0011 applied, schema 11; all programs RUNNING, the container
healthy. Resync's key cleanup checked against the live data: every key
directory is a domain's or the hostname's, nothing to remove.

CHANGELOG cut; pin 2.5.4 in deploy/docker-compose.yml, README, guide (and
its sample restore message); development.md "from pin" and the stage's row;
roadmap row and recommended order; stage 4 marked shipped in the plan. No
tag.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/roadmap.md

@@ -45,7 +45,7 @@ in `git log` and [CHANGELOG.md](../CHANGELOG.md).
 | from-header-binding | Hold a message's `From:` header against the application that sends it | shipped `2.4.0` | 9/9 | [plans/from-header-binding.md](plans/from-header-binding.md) |
 | panel-redesign | Panel redesign (accepted mockups, design contract) | shipped `2.0.0` | 27/27 | [plans/panel-redesign.md](plans/panel-redesign.md) |
 | schema-squash | Squash SQLite migrations into a 2.x baseline | built in panel-redesign (stage 1) | — | [plans/panel-redesign.md](plans/panel-redesign.md) |
-| audit-2026-10-12 | Follow-ups of the 2026-10-12 full-tree code audit, seven stages | in progress (stage 0 shipped `2.4.2`, stages 1+2 `2.5.0`, 2b `2.5.1`, 2c `2.5.2`, 3 `2.5.3`; next stage 4 → `2.5.4`) | 68/81 | [audit-2026-10-12.md](audit-2026-10-12.md) |
+| audit-2026-10-12 | Follow-ups of the 2026-10-12 full-tree code audit, seven stages | in progress (stage 0 shipped `2.4.2`, stages 1+2 `2.5.0`, 2b `2.5.1`, 2c `2.5.2`, 3 `2.5.3`, 4 `2.5.4`; next stage 5 → `2.6.0`) | 68/81 | [audit-2026-10-12.md](audit-2026-10-12.md) |
 
 **Recommended order** (not binding; owner, 2026-10-09: feature order follows
 development convenience): **panel-redesign** shipped as `2.0.0` (2026-10-11) and
@@ -55,7 +55,8 @@ shipped as `2.2.0` the same day, **panel-notifications** as `2.3.0` and
 **from-header-binding** as `2.4.0`. Stage 0 of
 [audit-2026-10-12](audit-2026-10-12.md) shipped as `2.4.2` (2026-10-14), its
 stages 1 and 2 as `2.5.0` the same day, stage 2b as `2.5.1`, stage 2c as
-`2.5.2` (2026-10-15), and stage 3 as `2.5.3` the same day.
+`2.5.2` (2026-10-15), and stages 3 and 4 as `2.5.3` and `2.5.4` the same
+day.
 Nothing is agreed after it: every remaining
 item is a candidate. panel-docs shipped in
 [CHANGELOG.md](../CHANGELOG.md) `[1.8.0]`; dmarc-reports in `[1.7.0]`