fix: detect IntelliJ IDEA and Android Studio from JetBrains Toolbox

The product-code allowlist introduced in 73f8361 was copied verbatim
from the old icon-only list, which never contained IU/IC/AI. As a
result, IntelliJ IDEA (Ultimate/Community) and Android Studio installed
via Toolbox were silently filtered out and never surfaced as external
tools.

Add IU, IC and AI to the allowlist, and ship matching 64x64 icons
sourced from the official Toolbox assets under
Resources/Images/ExternalToolIcons/JetBrains/.

Author: gadfly3173

src/Models/ExternalTool.cs

@@ -186,7 +186,7 @@ public void Cursor(Func<string> platformFinder)
 
         public void FindJetBrainsFromToolbox(Func<string> platformFinder)
         {
-            var supported = new List<string> { "CL", "DB", "DL", "DS", "GO", "JB", "PC", "PS", "PY", "QA", "QD", "RD", "RM", "RR", "WRS", "WS" };
+            var supported = new List<string> { "AI", "CL", "DB", "DL", "DS", "GO", "IC", "IU", "JB", "PC", "PS", "PY", "QA", "QD", "RD", "RM", "RR", "WRS", "WS" };
             var state = Path.Combine(platformFinder(), "state.json");
             if (File.Exists(state))
             {