add dolibarr api skills for read-only inspection

First two of an expected family of dolibarr-* skills:

- dolibarr/: platform reference — DOLAPIKEY auth, the voir_tous ACL
  trap, endpoint catalogue, the dol-curl.sh wrapper, .env credentials
  layout (gitignored, mode 600). Every future workflow skill depends
  on this one.
- dolibarr-invoice-audit/: first workflow — list KissMetrics invoices,
  audit one invoice end-to-end (JSON facts + PDF mandatory-mention
  checklist against the French legal corpus), audit the KissMetrics
  thirdparty record.

Live captures in examples/ include real audit findings to surface
to the Arcodange × KissMetrics cohort review: PDFs are missing
capital social, L.441-10 penalties, 40 € indemnity, L.123-22 / R.123-237;
KissMetrics thirdparty has no EIN (idprof1..6 all empty);
static/config/company.json holds placeholder values and a wrong
forme juridique (claims SAS, the real Dolibarr is SARL).

.gitignore hardened with *.credentials, secrets/, *.key, and an
explicit .claude/skills/**/.env pattern.

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

.claude/skills/dolibarr-invoice-audit/examples/audit-km-thirdparty.txt

@@ -0,0 +1,26 @@
+================================================================================
+ KissMetrics thirdparty audit — socid=1
+================================================================================
+  [OK] name               = 'KissMetrics'
+  [OK] client flag        = 'yes'
+  [OK] country_code       = 'US'
+  [OK] state_id           = '1167'
+  [OK] address            = '2850 34th Street North, 307'
+  [OK] zip                = '33713'
+  [OK] town               = 'St. Petersburg'
+  [OK] email              = 'evan@kissmetrics.io'
+  [XX] phone              = None
+  [XX] url                = None
+
+  idprof1..idprof6 (EIN slot for non-EU customers):
+      idprof1    = ''
+      idprof2    = ''
+      idprof3    = ''
+      idprof4    = ''
+      idprof5    = ''
+      idprof6    = ''
+  [XX] EIN present (any idprof populated)
+
+  array_options (Dolibarr extrafields): (none)
+
+  8 pass / 3 fail