feat(ai): enforce local-first routing

Keep external providers behind server consent, task, and prompt-cost gates while persisting actual provider provenance.

JobTrackerApi/Services/AiWorkspaceService.cs

@@ -134,12 +134,23 @@ public sealed class AiWorkspaceService : IAiWorkspaceService
         };
 
         var prompt = $"{instruction} {Guardrail}";
-        var result = await _ai.SummarizeSectionAsync(prompt, source, max, 120);
+        AiGenerationResult? generation;
+        try
+        {
+            generation = await _ai.GenerateSectionWithMetadataAsync(prompt, source, max, 120, ct);
+        }
+        catch (AiGenerationException)
+        {
+            throw new AiUnavailableException("The AI service could not generate this right now. Please try again in a moment.");
+        }
+        var result = generation?.Text;
         if (string.IsNullOrWhiteSpace(result))
         {
             throw new AiUnavailableException("The AI service could not generate this right now. Please try again in a moment.");
         }
 
+        var actualProvider = string.IsNullOrWhiteSpace(generation?.Provider) ? provider : generation.Provider;
+
         var interaction = new AiInteraction
         {
             OwnerUserId = ownerUserId,
@@ -147,8 +158,17 @@ public sealed class AiWorkspaceService : IAiWorkspaceService
             Module = module,
             Mode = mode,
             Title = title,
-            Provider = string.IsNullOrWhiteSpace(provider) ? "ai-service" : provider,
-            ResultJson = JsonSerializer.Serialize(new { text = result.Trim() }, Json),
+            Provider = string.IsNullOrWhiteSpace(actualProvider) ? "ai-service" : actualProvider,
+            ResultJson = JsonSerializer.Serialize(new
+            {
+                text = result.Trim(),
+                meta = new
+                {
+                    model = generation?.Model,
+                    fallbackReason = generation?.FallbackReason,
+                    routeReason = generation?.RouteReason,
+                },
+            }, Json),
             InputCharacterCount = prompt.Length + source.Length,
             OutputCharacterCount = result.Trim().Length,
             EstimatedTokenCount = EstimateTokens(prompt.Length + source.Length + result.Trim().Length),