stabilizaiton work - projects rework for maintenanceability and ui livening

src/__Libraries/StellaOps.Provcache.Api/ProvcacheEndpointExtensions.GetSingleChunk.cs

@@ -0,0 +1,45 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
+
+namespace StellaOps.Provcache.Api;
+
+public static partial class ProvcacheEndpointExtensions
+{
+    /// <summary>
+    /// GET /v1/provcache/proofs/{proofRoot}/chunks/{chunkIndex}
+    /// </summary>
+    private static async Task<IResult> GetSingleChunkAsync(
+        string proofRoot,
+        int chunkIndex,
+        [FromServices] IEvidenceChunkRepository chunkRepository,
+        ILogger<ProofsApiEndpoints> logger,
+        CancellationToken cancellationToken)
+    {
+        logger.LogDebug("GET /v1/provcache/proofs/{ProofRoot}/chunks/{ChunkIndex}", proofRoot, chunkIndex);
+
+        try
+        {
+            var chunk = await chunkRepository.GetChunkAsync(proofRoot, chunkIndex, cancellationToken);
+            if (chunk is null)
+            {
+                return Results.NotFound();
+            }
+
+            return Results.Ok(new ProofChunkResponse
+            {
+                ChunkId = chunk.ChunkId,
+                Index = chunk.ChunkIndex,
+                Hash = chunk.ChunkHash,
+                Size = chunk.BlobSize,
+                ContentType = chunk.ContentType,
+                Data = Convert.ToBase64String(chunk.Blob)
+            });
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Error getting chunk {ChunkIndex} for proof root {ProofRoot}", chunkIndex, proofRoot);
+            return InternalError("Chunk retrieval failed");
+        }
+    }
+}