feat(product-scope): gate Navigator facts, then reuse discover_scope (step 3)

Connects the Navigator's fact-gate to the existing reasoning discover_scope —
the Scope Engine decides only once the minimum (P0) facts are released.

- resolve_product_scope(canonical): if not ready_for_scope -> NEEDS_FACTS
  (missing_facts + suggested_questions, discover_scope NOT run); else project
  canonical->reasoning profile and run the EXISTING discover_scope exactly once
  -> RESOLVED with applicable/excluded/uncertain regulations.
- Environmental triggers surface ONLY as unsupported_domains (future_corpus_needed),
  never as a legal evaluation — transparency, no false completeness.
- POST /reasoning/product-scope (thin handler) returns case NEEDS_FACTS or RESOLVED.
- No new scope rules, no new regulations, no environmental-law evaluation, no UI,
  no Go, no RAG, no percent-compliance. Response types are application-level, not
  meta-model classes (freeze v1.0 untouched).
- 6 tests incl. discover_scope spy (0 calls when gated, exactly 1 when ready),
  category separation, environmental-as-unsupported-only. 47 tests green (existing
  reasoning MVP tests stay green), mypy clean, LOC ok.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend-compliance/compliance/product_scope/schemas.py

@@ -0,0 +1,63 @@
+"""Response schemas for the product-scope orchestrator (step 3).
+
+These are application/API types — NOT compliance-meta-model classes (architecture
+freeze v1.0 untouched). The scope verdict itself is produced by the existing
+`discover_scope`; nothing here adds scope rules.
+"""
+
+from __future__ import annotations
+
+from enum import Enum
+from typing import List, Optional
+
+from pydantic import BaseModel, Field
+
+from compliance.navigator.engine import CompletenessSummary
+from compliance.navigator.questions import NavigatorQuestion
+from compliance.profile.canonical import CanonicalProductRegulatoryProfile
+from compliance.reasoning.enums import Confidence
+from compliance.reasoning.schemas import (
+    ApplicableRegulation,
+    ExcludedRegulation,
+    UncertainRegulation,
+)
+
+
+class ScopeStatus(str, Enum):
+    NEEDS_FACTS = "needs_facts"  # P0 facts missing -> ask, do not decide
+    RESOLVED = "resolved"  # minimum facts present -> scope decided
+
+
+class UnsupportedDomain(BaseModel):
+    """A domain the product triggers but the corpus does not yet cover.
+
+    Surfaced for transparency (no false completeness) — NEVER a legal evaluation.
+    """
+
+    domain: str
+    trigger: str
+    status: str = "future_corpus_needed"
+    note: str = ""
+
+
+class RegulatoryScopeResult(BaseModel):
+    applicable_regulations: List[ApplicableRegulation] = Field(default_factory=list)
+    excluded_regulations: List[ExcludedRegulation] = Field(default_factory=list)
+    uncertain_regulations: List[UncertainRegulation] = Field(default_factory=list)
+    unsupported_domains: List[UnsupportedDomain] = Field(default_factory=list)
+    reasoning_summary: str = ""
+    confidence: Confidence = Confidence.MEDIUM
+
+
+class ProductScopeRequest(BaseModel):
+    product_profile: CanonicalProductRegulatoryProfile
+
+
+class ProductScopeResponse(BaseModel):
+    status: ScopeStatus
+    completeness_summary: CompletenessSummary
+    # case NEEDS_FACTS
+    missing_facts: List[str] = Field(default_factory=list)
+    suggested_questions: List[NavigatorQuestion] = Field(default_factory=list)
+    # case RESOLVED
+    regulatory_scope: Optional[RegulatoryScopeResult] = None