fix(scan): normalise patterns before building the AC dictionary - #59
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The Aho-Corasick dictionary was built from raw pattern text while payloads go through NFKC, zero-width stripping, and leetspeak cleaning. Patterns containing characters that normalise rewrites could never match. Add normalisePattern and apply it at dictionary build time so the AC alphabet matches CanonicalText. Fixes jp-046, jp-043, jp-038.
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The AC dictionary in NewScanStage was built from raw pattern strings, but
CanonicalText goes through NFKC, zero-width stripping, and leetspeak cleaning
in the normalise stage. Any pattern containing characters that those transforms
rewrite could never match because the dictionary and the searched text used
different alphabets.
Adds
normalisePattern(NFKC + stripZeroWidth + cleanLeetspeak, no URL/b64decode since those are payload-specific) and applies it at dictionary build
time. This revives 3 dead patterns:
<!-- ...):!maps toi, so<!in the dict never matched<iin canonical textstripZeroWidthremoved U+200B from payloads but not from the dictbase64):4maps toa, sobase64in the dict never matchedbase6ain canonical textTests added for all 3 cases. Existing patterns are unaffected (they contain no
characters that normalise rewrites). go vet + gofmt + full suite green.