log panes: lines wrap under their start instead of scrolling sideways

The owner, 2026-10-16, a phone screenshot of a message's Delivery log:
"На телефоне при просмотре лога, появляются две полосы. Мы это можем
поправить?" - the horizontal scroll bars Chrome on Android drew over a
pre whose mail.log lines were wider than it. As the mockup of 216f366:
sp-log wraps (pre-wrap, overflow-wrap: anywhere) and no longer scrolls;
log_pane writes each line as a block, sp-ll, with a 4ch hanging indent and
its newline inside it, so copied text keeps one line per line. One
partial: the Delivery log of a message, System log, the outbound queue's
listing.

Tests: TestLogPaneIsAPreWithEscapedLines reads the new shape; the page
tests' substrings stand; TestPanelCSSIsTheMockupStylesheet holds panel.css
to the mockup. go vet + go test (26 packages) and make e2e on the test
server for this tree. CHANGELOG [Unreleased] § Fixed.

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

CHANGELOG.md

@@ -5,6 +5,14 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
 
 ## [Unreleased]
 
+### Fixed
+
+- **Log panes wrap their lines instead of scrolling sideways**: a phone drew
+  two scroll bars over the Delivery log of a message, and the end of a
+  delivery line - `status=` and the reply - was out of sight. A long line
+  wraps, the rest indented under its start; copied text keeps one line per
+  line. The Delivery log, System log and the queue's listing.
+
 ## [2.9.0] - 2026-10-16
 
 The panel's DNS records read faster: a record DNS already holds as shown