Add global/local BLAST modes, full-length pairwise alignment view, standalone pairwise tool

feat(alignment): multi-method MSA (clustalo/muscle/kalign/mafft/tcoffee) with method selector (3b)

feat(alignment): pairwise global/local alignment via BLAST hit 'Align pair' (3a)

Fix MSA: use correct EBI result type 'fa' instead of 'aln-fasta' — confirmed via live API test

Fix MSA: dynamically discover EBI result types instead of hardcoding 'aln-fasta'

Fix MSA alignment: add Accept headers, result retry with delay, better error detail

Sprint 3-7: Alignment, Structure Viewer, Pathway Analysis, Utility Tools, analyze page fully live