inbound-antispam-panel: Inbound log, Why as a sheet; no Deny on a Postfix reject

Follows the two design commits before it (owner's decisions quoted
there).

Kit: a new component, Sheet / SheetRow (components.go), partials
sheet_tag and sheet (components.html), its rules in panel.css as in
theme.css, and its sample on the kit page next to status_tag. It is
the browser's popover: no script.

Inbound log: the Why column is gone; the decision tag opens a sheet
with who decided, then either the filter's verdict and its symbols one
a line (a detail the journal milter wrote) or the reply (a detail the
tailer read from mail.log - it starts with its code), and the subject
whole. The sheet's id is the journal row's. A row Postfix itself
refused no longer links to the filter lists.

Tests: the page fixture and view tests for the sheet's markup and
content (TestWhyRows), the link rule, three Deny and two Allow on the
mockup's six rows; e2e reads "Decided by" and "Reply" from the sheet
and wants no sender link on the refused row.

Seen: the fixture page with a sheet open, headless Edge at 1360 px -
the same as the accepted drawing.

Checked on the test server, uncommitted tree: go vet ./... ok,
go test ./... ok (22 packages), make e2e ok.

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

internal/web/view/templates/kit.html

@@ -31,6 +31,7 @@
       <thead><tr><th>Status</th><th>Tag</th><th>Bulma classes</th></tr></thead>
       <tbody>{{range .StatusRows}}
         <tr><td>{{.Words}}</td><td>{{template "tag" .Tag}}</td><td class="sp-mono sp-small">{{status_tag .Tag.Status}}</td></tr>{{end}}
+        <tr><td>a tag that opens a <code>sheet</code></td><td>{{template "sheet_tag" .Sheet}}</td><td class="sp-mono sp-small">button.tag + sp-sheet (popover)</td></tr>
       </tbody>
     </table></div>
     {{template "box_close"}}