fix(web-client): prevent IME input text repetition (#4975)

* fix(web-client): prevent IME input text repetition

Fix bug where composing multi-character strings via IME (e.g. Chinese input method) would write the entire string N times for N characters.

Previously, parse_stdin sent the entire input buffer as raw_bytes for each KeyEvent parsed from that buffer. When IME composes "你好" (2 chars), InputParser creates 2 KeyEvents, but both carried the full "你好" bytes, causing it to be written twice.

Now, when multiple events are parsed from one buffer, each Char KeyEvent carries only its own UTF-8 bytes. Single-event buffers (most ASCII input) remain unchanged.

Fixes #4974

* fix: guard per-char raw_bytes with modifiers check

Only use per-character UTF-8 encoding for unmodified Char events in multi-event buffers. Modified keys (e.g. Ctrl+C) retain the original buffer to preserve correct VT bytes. Also clarify the comment.

* test(web-client): cover IME raw byte handling

* rustfmt

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Co-authored-by: Aram Drevekenin <aram@poor.dev>

0 files changed, 0 insertions, 0 deletions