fix(tui): use brand terracotta for modal borders instead of theme blue

Modal boxes used `border: round $panel`, which resolves to a blue-gray
(#242f38) in the textual-dark theme - clashing with the terracotta accent
buttons inside. Anchor the border to the brand color (#d97757, themes.ACCENT)
so it stays consistent and theme-independent. Affects ConfirmModal and
GhosttyRequiredModal.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Welchost Contributors

src/welchost/tui/screens/modals.py

@@ -39,7 +39,8 @@ class ConfirmModal(ModalScreen[bool]):
     ConfirmModal { align: center middle; background: $background; }
     ConfirmModal #modal-box {
         width: 60; max-width: 90%; height: auto; padding: 1 2;
-        border: round $panel; background: $surface;
+        /* Brand terracotta (themes.ACCENT), not the theme's blue-gray $panel. */
+        border: round #d97757; background: $surface;
     }
     ConfirmModal #modal-msg { padding: 0 0 1 0; }
     ConfirmModal #modal-buttons { height: auto; text-align: center; padding: 1 0 0 0; }
@@ -103,7 +104,8 @@ class GhosttyRequiredModal(ModalScreen[None]):
     GhosttyRequiredModal { align: center middle; background: $background; }
     GhosttyRequiredModal #modal-box {
         width: 60; max-width: 90%; height: auto; padding: 1 2;
-        border: round $panel; background: $surface;
+        /* Brand terracotta (themes.ACCENT), not the theme's blue-gray $panel. */
+        border: round #d97757; background: $surface;
     }
     GhosttyRequiredModal #modal-msg { padding: 0 0 1 0; }
     GhosttyRequiredModal #modal-buttons { height: auto; text-align: center; padding: 1 0 0 0; }