ebd2f77770
- Changed hashline format to canonical `§` section headers and `"`/`"`/`≔` operations across grammar, parser, and docs. - Reworked range and op parsing so single anchors are valid, legacy `-`/`-=` ops error, and empty `≔` payloads now delete ranges. - Removed legacy `HL_EDIT_SEP`, `$HSEP$`, and `hsep` plumbing, adopting raw payload lines. - Updated execution, input, renderer, and streaming flows to use `HL_FILE_PREFIX` and `HL_OP_CHARS` helpers. - Updated session-stats parsing to `§`/`≔`/`"`/`"` format, patch envelopes, and bumped parser versions. - Removed the hashline-separator benchmark script and its PI_HL_SEP job orchestration.