* fix(stream): tolerate ~~~-fenced code and \-prefixed closer when decoding escaped newlines
_decode_escaped_newlines_outside_fences only recognised ``` fences, so replies
that used ~~~ fences (e.g. code blocks rendered by the model with
~~~python ...) kept literal backslash-n sequences escaped instead of decoding
the ones outside fences, and a fence whose closer was split as backslash+tilde
across chunks was misread mid-stream. Fixes#7262.
- detect the opening fence with (?:```|~~~) and remember which delimiter the
fence was opened with, so closing requires the same delimiter
- while inside a fence, hold back a closer that begins with a backslash so a
fence ending in backslash+tilde mid-stream is not misread; the held tail is
revisited on the next push and normalised on flush
- keep backtick hold semantics unchanged
* fix(mindie): preserve unclosed fences during newline decoding
Match one-shot decoding to streaming by choosing the earliest backtick or tilde opener and preserving the remainder when its matching closer is absent. Correct the string-return docstring and cover mixed delimiters across every two-chunk split and character-by-character streaming.
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Co-authored-by: Willem Jiang <willem.jiang@gmail.com>