fix: #12 lift sub-WCAG-AA text colors on 33 dark-bg sites

Replaces FAIL-level (<3:1) and WEAK (<4.5:1) --text-muted/--text-dim/
--text-faint/--text-dimmer/--accent-dim/--gold-dim values across all
33 affected sites. Targets: text-muted >=4.6:1 (WCAG AA),
text-dim/text-faint >=7:1 (WCAG AAA).

Shared palette pattern (15 sites: deinesei, fragina, ichbinaufbali,
ichbinaufbarley, insain, kainstress, kinowhow, knzlmgmt, kopffrai,
legalais, martinsiebels, schulfrai, smartin3, sorgenfrai, vonschraitter):
  --text-muted #44444f -> #7a7a8e (2.06 -> 4.71)
  --text-dim   #6e6e7a -> #9a9aab (3.93 -> 7.14)

Otto/mai-otto pattern (purple-tinted): #404068 -> #7373bb,
#7070a0 -> #9797d8.

Per-site fixes for kainco, kainefrage, kilitaer (olive), killegal,
killionaer, killuminati, killusion, killions, orakil (warm),
paragraphenraiter (gold), keinefreun, julietensity, billableaua,
allaisonme, allainallain, slopschild — each preserves its tint while
crossing the AA threshold.

Audit before: 31 FAIL, 2 WEAK / 33 sites flagged.
Audit after:  0 FAIL, 0 WEAK / 0 sites flagged.

Adds tools/contrast-audit.py (lifted from /tmp) so future edits can
re-run the regression check from the repo.

sites/smartin3.de/index.html

@@ -17,8 +17,8 @@
       --bg-card: #16161b;
       --border: #1e1e26;
       --text: #e8e8ed;
-      --text-dim: #6e6e7a;
-      --text-muted: #44444f;
+      --text-dim: #9a9aab;
+      --text-muted: #7a7a8e;
       --orange: #f97316;
       --orange-glow: rgba(249, 115, 22, 0.2);
       --orange-subtle: rgba(249, 115, 22, 0.08);