feat(ai): DB-only config + runtime provider selection via factory

API/ROLAC.API/Services/Ai/ClaudeExpenseAiService.cs

@@ -1,6 +1,5 @@
 using System.Net.Http.Json;
 using System.Text.Json;
-using Microsoft.Extensions.Options;
 using ROLAC.API.Data;
 
 namespace ROLAC.API.Services.Ai;
@@ -11,29 +10,33 @@ namespace ROLAC.API.Services.Ai;
 /// answer shape, so the model returns structured JSON in a <c>tool_use</c> block. The catalog,
 /// prompt, and id validation come from <see cref="ExpenseAiServiceBase"/>; this class only owns the
 /// Claude HTTP call + parse. Forced tool use works on every Claude model, so the configured
-/// <see cref="ClaudeOptions.Model"/> can be swapped (e.g. to a cheaper model) without code changes.
+/// model can be swapped (e.g. to a cheaper model) without code changes.
 /// </summary>
 public sealed class ClaudeExpenseAiService : ExpenseAiServiceBase
 {
+    private const string BaseUrl          = "https://api.anthropic.com/v1";
+    private const string AnthropicVersion = "2023-06-01";
+
     private readonly HttpClient _http;
-    private readonly ClaudeOptions _options;
+    private readonly IChurchAiConfigProvider _config;
     private readonly ILogger<ClaudeExpenseAiService> _logger;
 
     public ClaudeExpenseAiService(
         HttpClient http,
-        IOptions<ClaudeOptions> options,
+        IChurchAiConfigProvider config,
         AppDbContext db,
         ILogger<ClaudeExpenseAiService> logger)
         : base(db)
     {
         _http = http;
-        _options = options.Value;
+        _config = config;
         _logger = logger;
     }
 
     protected override async Task<ModelAnswer?> CallModelAsync(string prompt, CancellationToken ct)
     {
-        if (string.IsNullOrWhiteSpace(_options.ApiKey))
+        var cfg = await _config.GetAsync(ct);
+        if (string.IsNullOrWhiteSpace(cfg.ClaudeApiKey))
         {
             _logger.LogWarning("Claude API key is not configured; expense AI assist is disabled.");
             return null;
@@ -43,7 +46,7 @@ public sealed class ClaudeExpenseAiService : ExpenseAiServiceBase
         {
             var payload = new
             {
-                model = _options.Model,
+                model = cfg.ClaudeModel,
                 max_tokens = 1024,
                 tools = new[]
                 {
@@ -73,13 +76,13 @@ public sealed class ClaudeExpenseAiService : ExpenseAiServiceBase
                 },
             };
 
-            var url = $"{_options.BaseUrl}/messages";
+            var url = $"{BaseUrl}/messages";
             using var request = new HttpRequestMessage(HttpMethod.Post, url)
             {
                 Content = JsonContent.Create(payload),
             };
-            request.Headers.Add("x-api-key", _options.ApiKey);
-            request.Headers.Add("anthropic-version", _options.AnthropicVersion);
+            request.Headers.Add("x-api-key", cfg.ClaudeApiKey);
+            request.Headers.Add("anthropic-version", AnthropicVersion);
 
             using var response = await _http.SendAsync(request, ct);
             if (!response.IsSuccessStatusCode)