Drop three pieces of well-intentioned-but-fragile string mangling that
were quietly mutating model edit content:
- `maybeAutocorrectEscapedTabIndentation` in both hashline and atom edit
modes (plus the `PI_HASHLINE_AUTOCORRECT_ESCAPED_TABS` env toggle and
`isEscapedTabAutocorrectEnabled` helper). Literal `\\t` in edit content
is now preserved verbatim.
- `maybeWarnSuspiciousUnicodeEscapePlaceholder` and the
`runHashlinePreflightSanitizers` wrapper. The warning was misleading:
it flagged `\\uDDDD` as suspicious without distinguishing intentional
literal text from a likely-malformed escape, and it was the only
remaining caller.
- The hand-rolled JSON-unescape fallback in
`decodePartialJsonStringFragment` (renderer.ts). The fallback used
`String.fromCharCode` (mishandling lone surrogates) and only covered a
subset of JSON escapes, so the same fragment decoded one way mid-stream
and a different way after `JSON.parse` succeeded. Now we trim a
trailing partial `\\u`/odd-backslash escape and surface the raw
fragment if `JSON.parse` still fails.
can1357
848388c1a3