feat(cv): qualify templates and reliable local import processing

JobTrackerApi/Services/AvatarStorage.cs

@@ -1,5 +1,7 @@
 using System.Security.Cryptography;
 using System.Text;
+using JobTrackerApi.Data;
+using Microsoft.EntityFrameworkCore;
 
 namespace JobTrackerApi.Services;
 
@@ -7,6 +9,64 @@ public static class AvatarStorage
 {
     private const string FilePrefix = "file:";
 
+    public static async Task<string> StageAsync(string dataRoot, string userId, byte[] bytes, CancellationToken cancellationToken)
+    {
+        var key = Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes(userId))).ToLowerInvariant();
+        var folder = Path.Combine(dataRoot, "Avatars", key);
+        Directory.CreateDirectory(folder);
+        var path = Path.Combine(folder, $"avatar-{Guid.NewGuid():N}.png");
+        try { await File.WriteAllBytesAsync(path, bytes, cancellationToken); }
+        catch
+        {
+            TryDelete(FilePrefix + path);
+            throw;
+        }
+        return FilePrefix + path;
+    }
+
+    public static IEnumerable<string> PortraitFiles(string dataRoot, string ownerKey)
+    {
+        var root = Path.Combine(dataRoot, "Avatars");
+        var folder = Path.Combine(root, ownerKey);
+        if (ownerKey.Length != 64 || !ownerKey.All(Uri.IsHexDigit)
+            || !Directory.Exists(folder) || (File.GetAttributes(root) & FileAttributes.ReparsePoint) != 0
+            || (File.GetAttributes(folder) & FileAttributes.ReparsePoint) != 0) yield break;
+        foreach (var path in Directory.EnumerateFiles(folder, "avatar*", new EnumerationOptions { AttributesToSkip = FileAttributes.ReparsePoint, IgnoreInaccessible = true }))
+        {
+            var name = Path.GetFileName(path);
+            if (name is "avatar.png" or "avatar.jpg" or "avatar.webp"
+                || (name.StartsWith("avatar-", StringComparison.Ordinal) && name.EndsWith(".png", StringComparison.Ordinal)
+                    && name.Length == 43 && Guid.TryParseExact(name[7..^4], "N", out _))) yield return path;
+        }
+    }
+
+    public static async Task<int> SweepOrphansAsync(JobTrackerContext db, string dataRoot, DateTimeOffset now, CancellationToken token)
+    {
+        var root = Path.Combine(dataRoot, "Avatars");
+        if (!Directory.Exists(root) || (File.GetAttributes(root) & FileAttributes.ReparsePoint) != 0) return 0;
+        var candidates = Directory.EnumerateDirectories(root, "*", new EnumerationOptions { AttributesToSkip = FileAttributes.ReparsePoint, IgnoreInaccessible = true })
+            .Take(1000).SelectMany(folder => PortraitFiles(dataRoot, Path.GetFileName(folder)).Take(1000))
+            .Where(path => File.GetLastWriteTimeUtc(path) <= now.AddDays(-1).UtcDateTime)
+            .Take(1000).Select(path => FilePrefix + Path.GetFullPath(path)).ToList();
+        var referenced = (await db.Users.AsNoTracking().Where(user => candidates.Contains(user.AvatarImageDataUrl!))
+            .Select(user => user.AvatarImageDataUrl!).ToListAsync(token))
+            .ToHashSet(OperatingSystem.IsWindows() ? StringComparer.OrdinalIgnoreCase : StringComparer.Ordinal);
+        var removed = 0;
+        foreach (var candidate in candidates)
+        {
+            token.ThrowIfCancellationRequested();
+            if (!referenced.Contains(candidate) && TryDelete(candidate)) removed++;
+        }
+        return removed;
+    }
+
+    public static bool TryDelete(string? value)
+    {
+        try { Delete(value); return true; }
+        catch (IOException) { return false; }
+        catch (UnauthorizedAccessException) { return false; }
+    }
+
     public static async Task<string> StoreAsync(string dataRoot, string userId, byte[] bytes, string contentType, CancellationToken cancellationToken)
     {
         var userKey = Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes(userId))).ToLowerInvariant();