fix(v2): redefine AI actionability semantics + version the classifier (AI_CLASSIFIER_VERSION)

Production-readiness cycle. Classifier was excessively conservative (real
Run A: ACTIONABLE_NOW/UNASSIGNED_ACTIONABLE both 0) and made concrete
semantic mistakes on real tickets:
- #34419: technician "Rafael Brito" (internal) classified as WAITING_VENDOR
  waiting_for -- an internal technician is not a vendor.
- #37389: ticket had concrete open tasks ("Realizar um inventário das
  máquinas", "Alinhar o dia...") but was classified INSUFFICIENT_CONTEXT.
- Generic next_action ("Revisar chamado") repeated across unrelated
  tickets, proving nothing about real actionability.

Rewrote the system prompt (n8n/nodes/prepare-ai-prompt.node.js) with:
practical actionability definition ("suporte consegue fazer algo util
agora", explicit inclusion list); contatar-vs-aguardar distinction with
examples; WAITING_* requires positive evidence (action already taken AND
external dependency still open); technician-vs-vendor distinction citing
the TECNICO context field; STATUS Planejado alone != blocked/scheduled;
SCHEDULED requires an explicit date/window; mandatory chronological
interpretation (most recent apontamento wins over a superseded old
blocker); next_action must be concrete, with explicit accepted/rejected
examples; INSUFFICIENT_CONTEXT bar raised (ask "is there a diagnostic
step available even without full info" first).
n8n/nodes/prepare-ai-prompt.node.test.js: 10 new tests asserting each
rule's text is still present in the prompt (deterministic proxy --
behavioral proof comes from the real DEV run, inspected manually).

logic/classification.js: added AI_CLASSIFIER_VERSION=3 (stamped on every
valid classification); added a deterministic safety net (not just a
prompt hope) -- isWaitingForInternalTechnician() rejects WAITING_VENDOR
when waiting_for matches the ticket's own TECNICO field, routing to a new
fallback_reason 'ai_semantic_conflict' instead of accepting a known-wrong
semantic classification; added next_action genericness rejection
(isGenericNextAction) for ACTIONABLE_NOW/UNASSIGNED_ACTIONABLE only.
n8n/nodes/validate-ai-response.node.js: now passes the ticket into
validateAiClassification() so the technician guard has the facts it needs.

logic/cache.js: added buildCacheKey(contextHash, classifierVersion) ->
"<hash>:v<version>", stored in the same last_context_hash column (no
schema migration) -- bumping AI_CLASSIFIER_VERSION now forces a cache
miss on every ticket without manually clearing the Data Table.
n8n/nodes/decide-needs-ai.node.js / prepare-memoria-analise-record.node.js
updated to compute/persist the composite key.

logic/config.js: AI_MAX_CANDIDATES default raised 30->60 (now equals
CANDIDATE_POOL_SIZE) -- no candidate should go unanalyzed by an
artificial cap now that Run B already proved the cache makes repeat runs
cheap; AI_FALLBACK stays reserved for real provider failures. Also added
SEND_ENABLED (default false) and ENVIRONMENT config fields for the real
Slack send gate (used by logic/slack.js, next commit).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

n8n/nodes/validate-ai-response.node.js

@@ -18,8 +18,17 @@ return responseItems.map((responseItem, index) => {
     raw = null;
   }
 
-  const validation = validateAiClassification(raw);
-  const aiClassification = validation.valid ? validation.data : buildFallbackClassification('invalid_json');
+  // Passa o ticket pra validacao poder aplicar a guarda deterministica "tecnico interno nunca
+  // vira WAITING_VENDOR" (logic/classification.js -> isWaitingForInternalTechnician). Sem
+  // isso a validacao so olha o JSON cru, nunca os fatos do proprio chamado.
+  const validation = validateAiClassification(raw, original.ticket);
+  let aiClassification;
+  if (validation.valid) {
+    aiClassification = validation.data;
+  } else {
+    const isSemanticConflict = validation.errors.some((e) => e.includes('tecnico interno'));
+    aiClassification = buildFallbackClassification(isSemanticConflict ? 'ai_semantic_conflict' : 'invalid_json');
+  }
 
   return { json: { ...original, aiClassification } };
 });