Keyboard Macro Text Input Auto-Repeats First Character

I've found a persistent keyboard input buffer corruption issue when using external keyboard macros.
The first character received from a macro becomes "stuck" and repeats for all subsequent macro inputs, even across session restarts. Only clipboard operations can reset this state.

### Steps to reproduce
1. Configure a Logitech G HUB macro containing `. setup xxxxx`
2. Trigger the macro in WindTerm → outputs `.............` (dots only)
3. Trigger another macro containing `bitbake xxxxx` → still outputs `.............` (still dots)
4. Restart the SSH session → macro still produces dots
5. Copy any text to clipboard
6. Trigger the `bitbake` macro again → now outputs `bbbbbbbbbbbbb` (first character of new input)
7. Trigger the `. setup` macro → now outputs `bbbbbbbbbbbbb` (still stuck on 'b')
8. Copy different text again, trigger new macro with `test` → outputs `tttt`

choose "TEXT&EMOJIS"

### Expected behavior
Each macro should output its complete text string without character repetition

### Environment
WindTerm version: 2.7.0 on Windows
Macro tool: Logitech G HUB (Text marco)
Connection: SSH sessions to Linux servers, com port to serial device

Additional note: When the macro in Logitech G HUB is configured in Keystroke mode, the issue does not occur. It only happens when the macro is set to Text mode.

The issue names no source files or tests. Reproduce the problem in WindTerm 2.7.0 on Windows with Logitech G HUB Text-mode macros over SSH or serial, then trace the keyboard-input path and compare it with Keystroke mode. Done means each macro emits its complete text without repeating the first character, including after session restarts and clipboard changes.

Written by the indexing model from the issue text.