add dolibarr-tva-reconciliation, dolibarr-recurring-templates, dolibarr-data-snapshot

V3 bundle — three sibling skills under .claude/skills/, all read-only,
all depending on the dolibarr base skill.

dolibarr-tva-reconciliation:
- tva-by-month.sh: HT + TVA grouped by (year-month × tva_tx), ready
  for CA3 / CA12 transcription.
- tva-line-detail.sh: per-line audit trail with country-based bucket
  assignment (A1 domestic / A4 intra-UE autoliquidation / E2 export
  hors UE). Documents the French TVA mental model.
- Today every Arcodange line is E2 (KissMetrics, US, autoliquidation
  259-1° CGI). The skill scales for the day a French B2B is invoiced.

dolibarr-recurring-templates:
- list-templates.sh: probes /invoices/templates/{id} since there's no
  list endpoint. Stops after 5 consecutive empty responses.
- inspect-template.sh: full audit per template, with health checks.
- Surfaces that the "Kiss Metrics Invoice" template has frequency=0
  and nb_gen_done=0 — it is NOT auto-firing. Every KM invoice today
  was manually duplicated. Cohort-review implication: the deferred
  9-month cycle depends on Gabriel clicking "Generate" each month,
  not on a Dolibarr cron.

dolibarr-data-snapshot:
- snapshot.sh: bundles every read endpoint the dolibarr-* family uses
  into one JSON with a content_hash (sha256 of data only, excluding
  timestamp — so identical state hashes identically across runs).
- Use cases: cohort evidence packs, drift detection, archival before
  a known-risky UI change.
- V1 baseline summary captured at examples/snapshot-summary.txt
  (the ~246 KB snapshot file itself is intentionally not committed).

Also extends dolibarr/SKILL.md endpoint catalogue with
/invoices/templates/{id} (and its no-list-endpoint quirk + the
id-null sentinel for missing ids), plus links to the three new
sibling skills.

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

.claude/skills/dolibarr-tva-reconciliation/examples/tva-by-month.txt

@@ -0,0 +1,13 @@
+# TVA basis by month × rate — window=-inf → +inf
+
+month      tva_tx  count      basis HT         TVA  CA3 line
+----------------------------------------------------------------------
+2026-01    0.0000      3        510.00        0.00  (see tva-line-detail for cnty)
+2026-02    0.0000      2       7650.00        0.00  (see tva-line-detail for cnty)
+----------------------------------------------------------------------
+           TOTAL                      8160.00        0.00
+
+# Notes:
+#   - Lines with tva_tx==0 require country lookup to choose CA3 E2 (export hors UE)
+#     vs A4 (autoliquidation intra-UE). Run tva-line-detail.sh for that breakdown.
+#   - Credit notes (AVOIRs) show as negative HT and are correctly netted at basis.