fix: prevent double-processing of markdown to avoid nested links

Added check to detect if markdown has already been processed by looking
for our internal routes (/a/naddr1... or /p/npub1...) in markdown links.
If found, skip re-processing to prevent nested markdown link issues.

This addresses timing issues where markdown might be processed multiple
times, causing nostr URIs that were already converted to links to be
processed again, creating nested/duplicated markdown link structures.

src/utils/nostrUriResolver.tsx

@@ -123,6 +123,18 @@ function replaceNostrUrisSafely(
   const existingLinkCount = (markdown.match(/\]\(/g) || []).length
   console.log('[nostrUriResolver] Existing markdown links in input:', existingLinkCount)
   
+  // Check if markdown already contains our internal routes (indicates it's been processed)
+  // This prevents double-processing which can cause nested links
+  const hasInternalRoutes = /\]\(\/(?:a|p)\/[a-z0-9]+1[qpzry9x8gf2tvdw0s3jn54khce6mua7l]{58,}\)/i.test(markdown)
+  if (hasInternalRoutes) {
+    // Count how many internal routes we see
+    const internalRouteMatches = markdown.match(/\]\(\/(?:a|p)\/[a-z0-9]+1[qpzry9x8gf2tvdw0s3jn54khce6mua7l]{58,}\)/gi) || []
+    console.log('[nostrUriResolver] ⚠️ WARNING: Markdown appears to already be processed (contains', internalRouteMatches.length, 'internal routes like /a/naddr1... or /p/npub1...)')
+    console.log('[nostrUriResolver] Skipping re-processing to avoid nested links')
+    // Return as-is - don't process again
+    return markdown
+  }
+  
   // Track positions where we're inside a markdown link URL
   // Use a parser approach to correctly handle URLs with brackets/parentheses
   const linkRanges: Array<{ start: number, end: number }> = []