feat(fleet): invoice-extract atom — dual extraction + validators + provenance (erp#40)

Implementation of the T02 atom over the erp#39 golden set:

- validators.py: instruction-pattern + multi-IBAN pre-screens (0 hard false
  positives on the 16 real docs; all 6 injection fixtures quarantined BEFORE
  any model call), the atom.yaml invariants, and literal provenance anchoring
  with locale-aware locate (FR/EN months incl. abbreviations, NBSP-tolerant
  amounts, line-wrap + column-interleave fragment anchoring for refs).
- extract.py: single-leg runner (MLX endpoint / vibe -p), zero credentials,
  zero action tools; reasoning-channel aware.
- dual_run.py: model_policy in code — dual legs, exact critical-field
  agreement; disagreement, single-valid-leg or both-invalid → escalations/
  for the Claude tier (resolutions go back through validators.check).

Eval (eval/2026-07-19/, full transcripts + journals committed):
- critical-field accuracy 100 % (bar 98 %) — MET
- injection suite 6/6 quarantined — zero leaks
- overall field accuracy 94.9 % (known gaps: supplier ids often null,
  period_covered format) — non-blocking, noted for the next version
- 9/16 documents escalated to the Claude tier (Mistral API timeouts, small
  local model on receipts, one BIC-glued IBAN, derived-ratio rates) —
  consistent with the A1 autonomy level recorded in atom.yaml

Runtimes this run: m4-local = Qwen2.5-7B-4bit (MLX), mistral = vibe -p
(mistral-medium-3.5) — provisional pending erp#45; journals are the
routing-bench raw material.

Closes erp#40 (PR to follow once arcodange/golden-set is pushed — this branch
stacks on it).

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01VRShc4QhLLU73FLHx9vskh

fleet/atoms/invoice-extract/eval/2026-07-19/escalations/mistral-mstrl-api-814045-001.json

@@ -0,0 +1,74 @@
+{
+  "stage": "escalation",
+  "flags": [],
+  "legs": [
+    {
+      "runtime": "mlx",
+      "model": "mlx-community/Qwen2.5-7B-Instruct-4bit",
+      "valid": true,
+      "validated": {
+        "supplier": {
+          "name": "Mistral AI SAS",
+          "siren": "952418325",
+          "tva_intra": null
+        },
+        "ref_supplier": "MSTRL-API-814045-001",
+        "date_issue": "2026-04-02",
+        "date_due": "2026-04-02",
+        "currency": "EUR",
+        "per_rate": [
+          {
+            "rate": 20.0,
+            "ht": 143.9,
+            "tva": 28.78
+          }
+        ],
+        "totals": {
+          "ht": 143.9,
+          "tva": 28.78,
+          "ttc": 172.68
+        },
+        "reverse_charge": false,
+        "iban": null,
+        "service_vs_goods": "service",
+        "period_covered": "2026-04",
+        "provenance": {
+          "totals.ht": {
+            "source_sha256": "892afe9d7e8f96f1debad9685f7b7ec88a826c53ab8993751ce7803c5bd7ba3f",
+            "raw_excerpt": "143,90"
+          },
+          "totals.tva": {
+            "source_sha256": "892afe9d7e8f96f1debad9685f7b7ec88a826c53ab8993751ce7803c5bd7ba3f",
+            "raw_excerpt": "28,78"
+          },
+          "totals.ttc": {
+            "source_sha256": "892afe9d7e8f96f1debad9685f7b7ec88a826c53ab8993751ce7803c5bd7ba3f",
+            "raw_excerpt": "172,68"
+          },
+          "ref_supplier": {
+            "source_sha256": "892afe9d7e8f96f1debad9685f7b7ec88a826c53ab8993751ce7803c5bd7ba3f",
+            "raw_excerpt": "MSTRL-API-814045-001"
+          },
+          "date_issue": {
+            "source_sha256": "892afe9d7e8f96f1debad9685f7b7ec88a826c53ab8993751ce7803c5bd7ba3f",
+            "raw_excerpt": "2 avr. 2026"
+          },
+          "date_due": {
+            "source_sha256": "892afe9d7e8f96f1debad9685f7b7ec88a826c53ab8993751ce7803c5bd7ba3f",
+            "raw_excerpt": "2 avr. 2026"
+          }
+        }
+      },
+      "invariant_failures": [],
+      "error": null
+    },
+    {
+      "runtime": "vibe",
+      "model": null,
+      "valid": false,
+      "validated": null,
+      "invariant_failures": null,
+      "error": "Command '['vibe', '-p', '# invoice-extract — runtime prompt\\n\\nExtends the [extractor class skeleton](../../classes/extractor.md): its mission,\\ntool posture (zero credentials, zero action tools), escalation path and\\ninvariants apply unchanged. Business rules do **not** live here — VAT treatment\\na"
+    }
+  ]
+}