refactor: add diagnostic logging and modernize collection expressions

- Add Debug.WriteLine to VaultStorageService empty catch blocks for diagnostics
- Replace .ToList() with collection expressions [..] in fragment repositories
- Remove redundant comments in DatabaseSessionService and VaultStorageService

Co-Authored-By: Oz <oz-agent@warp.dev>

Journal.Core/Repositories/InMemoryFragmentRepository.cs

@@ -11,7 +11,7 @@ public class InMemoryFragmentRepository : IFragmentRepository
     {
         lock (_lock)
         {
-            return _store.ToList();
+            return [.. _store];
         }
     }
 
@@ -90,7 +90,7 @@ public class InMemoryFragmentRepository : IFragmentRepository
         if (string.IsNullOrWhiteSpace(q)) return [];
         lock (_lock)
         {
-            return _store.Where(f => f.Tags?.Any(t => !string.IsNullOrWhiteSpace(t) && t.Contains(q, StringComparison.OrdinalIgnoreCase)) == true).ToList();
+            return [.. _store.Where(f => f.Tags?.Any(t => !string.IsNullOrWhiteSpace(t) && t.Contains(q, StringComparison.OrdinalIgnoreCase)) == true)];
         }
     }
 
@@ -100,7 +100,7 @@ public class InMemoryFragmentRepository : IFragmentRepository
         if (string.IsNullOrWhiteSpace(q)) return [];
         lock (_lock)
         {
-            return _store.Where(f => !string.IsNullOrWhiteSpace(f.Type) && f.Type.Trim().Contains(q, StringComparison.OrdinalIgnoreCase)).ToList();
+            return [.. _store.Where(f => !string.IsNullOrWhiteSpace(f.Type) && f.Type.Trim().Contains(q, StringComparison.OrdinalIgnoreCase))];
         }
     }
 
@@ -119,7 +119,7 @@ public class InMemoryFragmentRepository : IFragmentRepository
             if (timeAfter.HasValue)
                 results = results.Where(f => f.Time > timeAfter.Value);
 
-            return results.ToList();
+            return [.. results];
         }
     }
 }

Journal.Core/Repositories/SqliteFragmentRepository.cs

@@ -82,9 +82,7 @@ public sealed class SqliteFragmentRepository(IDatabaseSessionService session) :
 
         var conn = _session.GetConnection();
         var all = ReadAllFragments(conn);
-        return all
+        return [.. all.Where(f => f.Tags.Any(t => t.Contains(q, StringComparison.OrdinalIgnoreCase)))];
-            .Where(f => f.Tags.Any(t => t.Contains(q, StringComparison.OrdinalIgnoreCase)))
-            .ToList();
     }
 
     public List<Fragment> GetByType(string type)
@@ -95,9 +93,7 @@ public sealed class SqliteFragmentRepository(IDatabaseSessionService session) :
 
         var conn = _session.GetConnection();
         var all = ReadAllFragments(conn);
-        return all
+        return [.. all.Where(f => f.Type.Contains(q, StringComparison.OrdinalIgnoreCase))];
-            .Where(f => f.Type.Contains(q, StringComparison.OrdinalIgnoreCase))
-            .ToList();
     }
 
     public List<Fragment> Search(string? type = null, string? tag = null, DateTimeOffset? timeAfter = null)
@@ -115,7 +111,7 @@ public sealed class SqliteFragmentRepository(IDatabaseSessionService session) :
         if (timeAfter.HasValue)
             results = results.Where(f => f.Time > timeAfter.Value);
 
-        return results.ToList();
+        return [.. results];
     }
 
     // ── Private helpers ──────────────────────────────────────────────

Journal.Core/Services/Database/DatabaseSessionService.cs

@@ -25,7 +25,6 @@ public sealed class DatabaseSessionService(IJournalDatabaseService database) : I
 
         lock (_lock)
         {
-            // If password or directory changed, close the old connection
             if (_connection is not null &&
                 (_password != password || _dataDirectory != dataDirectory))
             {

Journal.Core/Services/Vault/VaultStorageService.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics;
 using System.IO.Compression;
 using System.Globalization;
 using System.Security.Cryptography;
@@ -42,9 +43,9 @@ public class VaultStorageService(IVaultCryptoService crypto) : IVaultStorageServ
                     {
                         File.Delete(vaultFile);
                     }
-                    catch
+                    catch (Exception ex)
                     {
-                        // Legacy file cleanup should never block loading.
+                        Debug.WriteLine($"[VaultStorageService] Failed to delete legacy vault file {fileName}: {ex.Message}");
                     }
                     continue;
                 }
@@ -59,11 +60,11 @@ public class VaultStorageService(IVaultCryptoService crypto) : IVaultStorageServ
                 }
                 catch (CryptographicException)
                 {
-                    // Wrong password for this vault file; continue trying others.
+                    Debug.WriteLine($"[VaultStorageService] Decryption failed for {fileName} (likely wrong password)");
                 }
-                catch
+                catch (Exception ex)
                 {
-                    // Non-password vault read/decrypt/extract error; continue loading others.
+                    Debug.WriteLine($"[VaultStorageService] Failed to load vault {fileName}: {ex.GetType().Name} - {ex.Message}");
                 }
             }
 
@@ -177,7 +178,6 @@ public class VaultStorageService(IVaultCryptoService crypto) : IVaultStorageServ
             }
         }
 
-        // Final attempt should throw with the underlying exception if deletion still fails.
         Directory.Delete(dataDirectory, recursive: true);
     }