fix: resolve unused variables in backend utils

Fixed @typescript-eslint/no-unused-vars errors in:
- starter.ts: removed unused error variables (2 fixes)
- auto-ssl-setup.ts: removed unused error variable (1 fix)
- ssh-key-utils.ts: removed unused error variables (3 fixes)
- user-crypto.ts: removed unused error variables (5 fixes)
- data-crypto.ts: removed unused plaintextFields and error variables (2 fixes)
- simple-db-ops.ts: removed unused parameters _userId and _tableName (2 fixes)

Total: 15 unused variable errors fixed

Co-Authored-By: Claude <noreply@anthropic.com>

src/backend/starter.ts

@@ -75,7 +75,7 @@ import { systemLogger, versionLogger } from "./utils/logger.js";
           version = foundVersion;
           break;
         }
-      } catch (error) {
+      } catch {
         continue;
       }
     }
@@ -128,7 +128,7 @@ import { systemLogger, versionLogger } from "./utils/logger.js";
       process.exit(1);
     });
 
-    process.on("unhandledRejection", (reason, promise) => {
+    process.on("unhandledRejection", (reason, _promise) => {
       systemLogger.error("Unhandled promise rejection", reason, {
         operation: "error_handling",
       });

src/backend/utils/auto-ssl-setup.ts

@@ -101,7 +101,7 @@ export class AutoSSLSetup {
     try {
       try {
         execSync("openssl version", { stdio: "pipe" });
-      } catch (error) {
+      } catch {
         throw new Error(
           "OpenSSL is not installed or not available in PATH. Please install OpenSSL to enable SSL certificate generation.",
         );

src/backend/utils/data-crypto.ts

@@ -97,7 +97,7 @@ class DataCrypto {
     let migratedFieldsCount = 0;
 
     try {
-      const { needsMigration, plaintextFields } =
+      const { needsMigration } =
         await LazyFieldEncryption.checkUserNeedsMigration(
           userId,
           userDataKey,
@@ -452,7 +452,7 @@ class DataCrypto {
       );
 
       return decrypted === testData;
-    } catch (error) {
+    } catch {
       return false;
     }
   }

src/backend/utils/simple-db-ops.ts

@@ -131,11 +131,10 @@ class SimpleDBOps {
     table: SQLiteTable<any>,
     tableName: TableName,
     where: unknown,
-    _userId: string,
   ): Promise<unknown[]> {
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
     const result = await getDb()
       .delete(table)
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
       .where(where as any)
       .returning();
 
@@ -152,10 +151,7 @@ class SimpleDBOps {
     return DataCrypto.getUserDataKey(userId) !== null;
   }
 
-  static async selectEncrypted(
-    query: unknown,
-    _tableName: TableName,
-  ): Promise<unknown[]> {
+  static async selectEncrypted(query: unknown): Promise<unknown[]> {
     const results = await query;
 
     return results as unknown[];

src/backend/utils/ssh-key-utils.ts

@@ -49,7 +49,7 @@ function detectKeyTypeFromContent(keyContent: string): string {
       }
 
       return "ssh-rsa";
-    } catch (error) {
+    } catch {
       return "ssh-rsa";
     }
   }
@@ -240,7 +240,7 @@ export function parseSSHKey(
             } else {
               publicKey = "";
             }
-          } catch (error) {
+          } catch {
             publicKey = "";
           }
 
@@ -318,7 +318,7 @@ export function detectKeyType(privateKeyData: string): string {
       return "unknown";
     }
     return parsedKey.type || "unknown";
-  } catch (error) {
+  } catch {
     return "unknown";
   }
 }

src/backend/utils/user-crypto.ts

@@ -195,7 +195,7 @@ class UserCrypto {
       DEK.fill(0);
 
       return true;
-    } catch (error) {
+    } catch {
       await this.setupOIDCUserEncryption(userId);
       return true;
     }
@@ -275,7 +275,7 @@ class UserCrypto {
       this.logoutUser(userId);
 
       return true;
-    } catch (error) {
+    } catch {
       return false;
     }
   }
@@ -298,7 +298,7 @@ class UserCrypto {
       DEK.fill(0);
 
       return true;
-    } catch (error) {
+    } catch {
       return false;
     }
   }
@@ -417,7 +417,7 @@ class UserCrypto {
       }
 
       return JSON.parse(result[0].value);
-    } catch (error) {
+    } catch {
       return null;
     }
   }
@@ -457,7 +457,7 @@ class UserCrypto {
       }
 
       return JSON.parse(result[0].value);
-    } catch (error) {
+    } catch {
       return null;
     }
   }