components: libc: fix array overflow in rt_object name assignment

[KennethLiu61]

[Problem Description]
When assigning name to rt_object, strncpy() uses size equal to RT_NAME_MAX, which causes missing null-terminator and overflows into adjacent 'type' field. This corruption leads to unexpected system behavior.

[Problem Analysis]
The rt_object structure defines:
| char name[RT_NAME_MAX] | -> buffer
| rt_uint8_t type | -> adjacent field

Original code calculates size as:
size = end - first + 1;
if (size > RT_NAME_MAX) size = RT_NAME_MAX;

When size equals RT_NAME_MAX, strncpy() will copy exactly RT_NAME_MAX bytes without adding terminating '\0', causing two issues:

1. name buffer is not null-terminated
2. The implicit null-byte writes beyond name[] into type field

[Solution]
Change boundary check from:
if (size > RT_NAME_MAX) size = RT_NAME_MAX;
to:
if (size >= RT_NAME_MAX) size = RT_NAME_MAX - 1;

This ensures:

1. Always leaves space for null-terminator
2. Prevents overflow into type field
3. Maintains maximum valid name length (RT_NAME_MAX-1 + '\0')

拉取/合并请求描述：(PR description)

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代码质量 Code Quality：

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

• 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
• 代码风格正确，包括缩进空格，命名及其他风格 Style guide is adhered to, including spacing, naming and other styles
• 没有垃圾代码，代码尽量精简，不包含#if 0代码，不包含已经被注释了的代码 All redundant code is removed and cleaned up
• 所有变更均有原因及合理的，并且不会影响到其他软件组件代码或BSP All modifications are justified and not affect other components or BSP
• 对难懂代码均提供对应的注释 I've commented appropriately where code is tricky
• 代码是高质量的 Code in this PR is of high quality
• 已经使用formatting 等源码格式化工具确保格式符合RT-Thread代码规范 This PR complies with RT-Thread code specification
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