Open-source release: pipeline code, raw logs, derived data, licences, tests

Adds src/ (scripts, raw measurement logs, derived data, report source),
tests/, LICENSE (MIT, code) and LICENSE-DATA.md (CC BY 4.0 for the survey's
data; third-party terms). The report is updated to the current site; the
v1 and v2 data hand-off files are unchanged.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/paths.mjs

@@ -0,0 +1,6 @@
+// Repository-relative paths, so the checks run from the quest tree and from the public repository alike.
+import { existsSync } from 'fs';
+export const ROOT = new URL('../', import.meta.url).pathname;
+export const PAGE = (p) => 'file://' + ROOT + 'src/' + p;
+// the hand-off files sit in src/handoff/ in the quest tree and at the repository root in the public copy
+export const HAND = (f) => existsSync(ROOT + 'src/handoff/' + f) ? ROOT + 'src/handoff/' + f : ROOT + f;