Feature: Add dynamic model selection to ViewReceipt page

Enhance receipt parsing model selection:
- Fetch available models from LlamaCpp server dynamically
- Show loaded/unloaded status in model dropdown
- Persist selected model to appsettings.json
- Read default model from AI:ReceiptParsingModel config
- Inject LlamaCppVisionClient and IConfiguration dependencies

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

MoneyMap/Pages/ViewReceipt.cshtml.cs

@@ -4,6 +4,8 @@ using Microsoft.EntityFrameworkCore;
 using MoneyMap.Data;
 using MoneyMap.Models;
 using MoneyMap.Services;
+using System.Text.Json;
+using System.Text.Json.Nodes;
 
 namespace MoneyMap.Pages
 {
@@ -12,22 +14,33 @@ namespace MoneyMap.Pages
         private readonly MoneyMapContext _db;
         private readonly IReceiptManager _receiptManager;
         private readonly IEnumerable<IReceiptParser> _parsers;
+        private readonly LlamaCppVisionClient _llamaClient;
+        private readonly IConfiguration _config;
+        private readonly IWebHostEnvironment _env;
 
         public ViewReceiptModel(
             MoneyMapContext db,
             IReceiptManager receiptManager,
-            IEnumerable<IReceiptParser> parsers)
+            IEnumerable<IReceiptParser> parsers,
+            LlamaCppVisionClient llamaClient,
+            IConfiguration config,
+            IWebHostEnvironment env)
         {
             _db = db;
             _receiptManager = receiptManager;
             _parsers = parsers;
+            _llamaClient = llamaClient;
+            _config = config;
+            _env = env;
         }
 
         public Receipt? Receipt { get; set; }
         public List<ReceiptLineItem> LineItems { get; set; } = new();
         public List<ReceiptParseLog> ParseLogs { get; set; } = new();
         public List<ParserOption> AvailableParsers { get; set; } = new();
+        public List<LlamaCppModel> AvailableModels { get; set; } = new();
         public string ReceiptUrl { get; set; } = "";
+        public string SelectedModel => _config["AI:ReceiptParsingModel"] ?? "gpt-4o-mini";
 
         [TempData]
         public string? SuccessMessage { get; set; }
@@ -59,6 +72,9 @@ namespace MoneyMap.Pages
                 FullName = p.GetType().Name
             }).ToList();
 
+            // Get available LlamaCpp models
+            AvailableModels = await _llamaClient.GetAvailableModelsAsync();
+
             return Page();
         }
 
@@ -94,6 +110,12 @@ namespace MoneyMap.Pages
                 return RedirectToPage(new { id });
             }
 
+            // Save selected model to config if it changed
+            if (!string.IsNullOrEmpty(model) && model != SelectedModel)
+            {
+                await SaveSelectedModelAsync(model);
+            }
+
             var result = await selectedParser.ParseReceiptAsync(id, model);
 
             if (result.IsSuccess)
@@ -108,6 +130,33 @@ namespace MoneyMap.Pages
             return RedirectToPage(new { id });
         }
 
+        private async Task SaveSelectedModelAsync(string model)
+        {
+            try
+            {
+                var appSettingsPath = Path.Combine(_env.ContentRootPath, "appsettings.json");
+                var json = await System.IO.File.ReadAllTextAsync(appSettingsPath);
+                var jsonNode = JsonNode.Parse(json);
+
+                if (jsonNode == null) return;
+
+                // Ensure AI section exists
+                if (jsonNode["AI"] == null)
+                {
+                    jsonNode["AI"] = new JsonObject();
+                }
+
+                jsonNode["AI"]!["ReceiptParsingModel"] = model;
+
+                var options = new JsonSerializerOptions { WriteIndented = true };
+                await System.IO.File.WriteAllTextAsync(appSettingsPath, jsonNode.ToJsonString(options));
+            }
+            catch
+            {
+                // Silently fail - not critical if we can't save the preference
+            }
+        }
+
         public class ParserOption
         {
             public string Name { get; set; } = "";