fix(amethyst): restore no-preview suppression of invoice/withdraw UI

Audit of the rich-text convergence found a behavior regression: the Android
RichTextSegmentRenderer.Payment ignored canPreview and always rendered the
interactive MayBeInvoicePreview / MayBeWithdrawal UI. The original
RenderWordWithoutPreview switchboard deliberately showed plain text for
invoice and withdraw segments when previews are suppressed ("Don't offer to
pay invoices" / "Don't offer to withdraw"). Branch on canPreview for those two;
Cashu and Clink stay unconditional (they decode locally, network only on tap),
matching the original.

Verified: :amethyst play debug compiles.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LUiGxXMbjVmgspa1X15o1V

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/AmethystRichText.kt

@@ -163,8 +163,11 @@ class AmethystRichTextSegmentRenderer(
         modifier: Modifier,
     ) {
         when (segment) {
-            is InvoiceSegment -> MayBeInvoicePreview(segment.segmentText, accountViewModel)
-            is WithdrawSegment -> MayBeWithdrawal(segment.segmentText, accountViewModel)
+            // Matches the original no-preview switchboard: don't surface a pay/withdraw
+            // affordance when previews are suppressed — show the raw text instead.
+            is InvoiceSegment -> if (canPreview) MayBeInvoicePreview(segment.segmentText, accountViewModel) else Text(segment.segmentText)
+            is WithdrawSegment -> if (canPreview) MayBeWithdrawal(segment.segmentText, accountViewModel) else Text(segment.segmentText)
+            // Cashu + Clink decode locally (network only on tap), so they render in both modes.
             is CashuSegment -> CashuPreview(segment.segmentText, accountViewModel)
             is ClinkOfferSegment -> ClinkOfferPreview(segment.offer, accountViewModel, nav)
             else -> Text(segment.segmentText)