Restore NSIS bootstrap installer page

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

contrib/nsis/setup.nsi

@@ -32,6 +32,9 @@ RequestExecutionLevel user
 !insertmacro MUI_PAGE_WELCOME
 !insertmacro MUI_PAGE_DIRECTORY
 
+; Bootstrap page
+Page custom BootstrapPage
+
 !insertmacro MUI_PAGE_INSTFILES
 !insertmacro MUI_PAGE_FINISH
 
@@ -40,6 +43,34 @@ RequestExecutionLevel user
 
 !insertmacro MUI_LANGUAGE "English"
 
+; Bootstrap selection variable
+Var BootstrapChoice
+
+; Bootstrap page function
+Function BootstrapPage
+  !insertmacro MUI_HEADER_TEXT "Blockchain Sync" "Choose how to synchronize the blockchain"
+  
+  nsDialogs::Create 1018
+  Pop $0
+  
+  ${NSD_CreateLabel} 0 10u 100% 20u "The Triangles blockchain requires ~1GB of data. Choose sync method:"
+  Pop $0
+  
+  ${NSD_CreateRadioButton} 10u 40u 100% 12u "Download bootstrap (~1.3GB) — Recommended (fast)"
+  Pop $1
+  ${NSD_Check} $1
+  
+  ${NSD_CreateRadioButton} 10u 60u 100% 12u "Sync from network — Slow (may take days)"
+  Pop $2
+  
+  ${NSD_CreateLabel} 10u 80u 100% 30u "Bootstrap will download a recent blockchain snapshot, saving hours or days of sync time. Network bandwidth required: ~1.3GB."
+  Pop $0
+  
+  nsDialogs::Show
+  
+  ${NSD_GetState} $1 $BootstrapChoice
+FunctionEnd
+
 Section "Install"
   SetOutPath "$INSTDIR"
 
@@ -53,6 +84,25 @@ Section "Install"
   ; Create data directory
   CreateDirectory "$APPDATA\Triangles"
 
+  ; Download blockchain bootstrap if selected
+  ${If} $BootstrapChoice == ${BST_CHECKED}
+    DetailPrint "Downloading blockchain bootstrap..."
+    inetc::get /CAPTION "Downloading Blockchain" /CANCELTEXT "Skip" \
+      "http://bootstrap.cryptographic-triangles.org/tri-blockchain.tar.gz" \
+      "$TEMP\tri-blockchain.tar.gz" /END
+    Pop $0
+    ${If} $0 == "OK"
+      DetailPrint "Extracting blockchain..."
+      nsExec::ExecToLog '"$INSTDIR\7z.exe" x "$TEMP\tri-blockchain.tar.gz" -o"$TEMP" -y'
+      nsExec::ExecToLog '"$INSTDIR\7z.exe" x "$TEMP\tri-blockchain.tar" -o"$APPDATA\Triangles" -y'
+      Delete "$TEMP\tri-blockchain.tar.gz"
+      Delete "$TEMP\tri-blockchain.tar"
+      DetailPrint "Blockchain bootstrap installed!"
+    ${Else}
+      DetailPrint "Bootstrap download failed or skipped — will sync from network"
+    ${EndIf}
+  ${EndIf}
+
   ; Uninstaller
   WriteUninstaller "$INSTDIR\uninstall.exe"