core: cleaner error output and more flexible custom tool directories

- Removed debug console.log when dependency installation fails so users see clean warning messages instead of raw error dumps
- Fixed database connection cleanup to prevent resource leaks between sessions
- Added support for loading custom tools from both .opencode/tool (singular) and .opencode/tools (plural) directories, matching common naming conventions

packages/opencode/src/config/config.ts

@@ -288,7 +288,6 @@ export namespace Config {
     // Install any additional dependencies defined in the package.json
     // This allows local plugins and custom tools to use external packages
     await Npm.install(dir).catch((err: any) => {
-      console.log(err)
       log.warn("failed to install dependencies", { dir, error: err.message })
     })
   }

packages/opencode/src/storage/db.ts

@@ -109,6 +109,7 @@ export namespace Database {
 
   export function close() {
     Client().$client.close()
+    Client.reset()
   }
 
   export type TxOrDb = Transaction | Client