fix: NGS fallback to Python aligner when native tools missing; add missing re import in sequence_utils

refactor: require native samtools/minimap2, delete hand-rolled BAM/BAI code

fix: correct BGZF virtual offsets in BAI, fix duplicate-read bug, install minimap2 everywhere

fix(ngs): dynamic locus + SAM-first igv.js for reliable genome browser

fix: repair BAI index generation and BAM record format for igv.js compatibility

fix(ngs): correct BAM record format and BAI index for igv.js

feat(ngs): pure-Python SAM to BAM converter with BGZF + BAI index for igv.js

fix: igv.js white screen — CIGAR ops, qual strings, locus format

feat: add igv.js genome browser + proper 6-step NGS pipeline

feat: add full 6-step NGS pipeline + fix sequencing WinError 193