feat(select-menu): add optionMeta slot and show repo details in create dialog

Add an optional optionMeta snippet to SelectMenu to render richer,
right-aligned content per option (falls back to option.meta when not
provided). Update SelectMenu markup to render optionMeta if present.

Style adjustments for .select-menu-option-meta to align items, allow
inline SVGs, and preserve spacing/coloring.

Use the new slot in CreateReviewDialog:
- supply grouped repository options (owner + name) instead of raw names
- show a branch icon for each option and a lock icon + last-updated date
  in the option meta
- add helpers repositoryById and formatUpdatedAt to resolve repository
  data for the meta snippet

No breaking changes: legacy option.meta still works when optionMeta is
not supplied.

src/app.css

@@ -327,12 +327,16 @@
   .select-menu-option:hover .select-menu-option-icon { color: var(--color-accent); }
   .select-menu-option-icon svg { color: inherit; }
   .select-menu-option-meta {
+    display: inline-flex;
+    align-items: center;
+    gap: 5px;
     flex: 0 0 auto;
     color: var(--color-ink-faint);
     font-size: 9.5px;
     font-weight: 650;
     letter-spacing: 0;
   }
+  .select-menu-option-meta svg { color: inherit; }
   .select-menu-option svg { color: var(--color-primary); }
   .select-menu-option:hover:not(:disabled), .select-menu-option.active:not(:disabled) {
     border-color: var(--color-border-subtle);