Extend SCANNER_PROBE_RE for 2026-07-19 secret-file scanner sweep (7 shapes)

Scanner-probe sweep 2026-07-19 12:50 UTC leaked 7 warn/navigation/page_not_found rows that should be down-tiered by SCANNER_PROBE_RE in src/lib/not-found-classify.ts (same class as prior PLUTO-442/450/453/462/498 classifier extensions). Paths: /.npmrc /.boto /.s3cfg /web.config /webpack-stats.json /_debugbar/open /__/firebase/init.json — a sequential secret/config-file scanner sweep, all correctly 404'd, zero user/security impact (the 404 is correct defensive behavior; this WI only stops the warn-noise + PM-DM leak, does NOT change any auth/gate). Root cause: none match the current regex — the firebase arm (line 93) requires a single path-segment + firebase*.json filename, but /__/firebase/init.json has two segments and filename init.json; the other six shapes aren't present. Fold these into SCANNER_PROBE_RE so they classify as info/security/no-alert. Verify each addition is collision-free against legit routes (per the branch-order note ~line 199) — all 7 are non-legit-in-a-Next-app shapes (IIS web.config, webpack build artifact, Laravel debugbar, firebase-hosting reserved, npm/boto/s3 cred dotfiles) so safe, but confirm no over-match. Class-S: single file, security-inert (down-tier only), reversible.