feat(console): add shell component with pipeline and operator support

Add new esp_shell component providing Unix-like shell functionality:
- Pipeline support with '|' operator for command chaining
- File output with support for '>' or '>>' for append.
- Multiple command operators: ';' (continue), '&&' (break on fail), '||' (break on success)
- Asynchronous command execution using console task API
- Real-time I/O handling with select() for stdin/stdout/stderr
- Proper resource management and error handling
- Support for Ctrl+D EOF detection, will support escaping of if a
  program like grep

Enables complex command sequences and data flow between commands
similar to traditional Unix shells.

Author: jimmyw

components/console/CMakeLists.txt

@@ -4,7 +4,8 @@ set(srcs "commands.c"
          "esp_console_common.c"
          "esp_console_repl_internal.c"
          "split_argv.c"
-         "linenoise/linenoise.c")
+         "linenoise/linenoise.c"
+         "shell.c")
 
 set(requires vfs)
 

components/console/esp_shell.h

@@ -0,0 +1,10 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#pragma once
+
+#include <stdbool.h>
+
+esp_err_t esp_shell_run(char *command_line, int *cmd_ret);