fix: correct tax-app exclusion rationale

tax-app is a demo app I built for an upcoming YC channel video,
not an "import-dominated history" as the previous commit claimed.
Excluded because it's not production shipping work, not because
of an import commit.

Updated rationale in scripts/garry-output-comparison.ts's
EXCLUDED_REPOS constant, in docs/ON_THE_LOC_CONTROVERSY.md's
method section + conclusion, and in the README hero wording
("one demo repo" vs the earlier "repos dominated by imported code").

Numbers unchanged — the exclusion itself is the same, just the
reason.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/garry-output-comparison.ts

@@ -38,12 +38,12 @@ const GARRY_EMAILS = [
 
 const TARGET_YEARS = [2013, 2026];
 
-// Repos to skip entirely because their activity is dominated by imported code
-// (initial commit that vendors an upstream codebase) rather than authored work.
-// When the script is pointed at one of these, it emits a stderr note and exits
-// without writing a per-repo JSON. Add more via PR with a one-line rationale.
+// Repos to skip entirely because they're not real shipping work (demos, spikes,
+// vendored imports, throwaway experiments). When the script is pointed at one
+// of these, it emits a stderr note and exits without writing a per-repo JSON.
+// Add more via PR with a one-line rationale.
 const EXCLUDED_REPOS: Record<string, string> = {
-  'tax-app': 'single 104K-line initial import, not authored code',
+  'tax-app': 'demo app for an upcoming YC channel video, not production shipping work',
 };
 
 type PerYearResult = {