style(ui): make docked dialog look more like a Torn panel (full-width, accent border)

Previously the .tat-root.tat-anchored rule centered the dialog with a
720px max-width and no extra border, which made it look like a floating
widget squeezed into the page rather than an embedded panel. The
Torn gym page reference is a full-width panel with a thin dark border
and a red top accent line.

Changes:
- margin: 0 0 12px 0 (full-width, no centering)
- max-width: none (span the content area)
- border-radius: 0 (Torn panels are flat, not rounded)
- border: 1px solid #444 with border-top: 2px solid #c00 (red accent)
- padding: 16px 20px (more breathing room, matching Torn panels)
- .tat-root.tat-anchored .tat-header { cursor: default } (drag is
  disabled in anchored mode, so the move cursor was misleading)

Free-floating mode is unchanged: the .tat-root base rule keeps its
rounded shadowed look and .tat-header keeps cursor: move.

Mirrored into the embedded TAT_STYLE in the bundle to keep the source
and bundle in lockstep.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/ui.js

@@ -10,10 +10,15 @@ const STYLE = `
 }
 .tat-root.tat-anchored {
   position: static;
-  margin: 0 auto 12px;
+  margin: 0 0 12px 0;
-  max-width: 720px;
+  max-width: none;
   box-shadow: none;
+  border-radius: 0;
+  border: 1px solid #444;
+  border-top: 2px solid #c00;
+  padding: 16px 20px;
 }
+.tat-root.tat-anchored .tat-header { cursor: default; }
 .tat-header {
   display: flex; justify-content: space-between; align-items: center;
   padding-bottom: 8px; margin-bottom: 10px;