CI's coverage gate rejected `ansi.ts` after the state normalization: the new
fold carries shapes the existing cases never reached.
Added, each expectation checked against a real terminal where the terminal is
the authority — three of my first guesses were wrong and the implementation
was right:
- `48;2;R;G;B` (the extended-background arm and its 4-parameter span), a bright
foreground and background (`91`/`101`, which resolve to `--dsw-*` tokens
rather than literal rgb), a `38` with no kind byte, re-opening an attribute
already in force, and the bare `\x1b[m` reset.
- Clearing a wide pair from the spacer side: `中x\r\bA` shows `A x`, since the
backspace clamps at column 0 and writing the lead blanks its spacer instead
of letting the `x` slide left. An erase reaching the lead does the same, so
`中x\x1b[1K|` shows three blanks before the bar.
Chinesezjc
dffb5c888f