feat(infospace): add schema compliance validator (S1.2)

Deterministic validation of EntityMeta against declarative schemas:
section presence/word counts, heading format, domain enum values.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

markitect/infospace/schema.py

@@ -0,0 +1,144 @@
+"""
+Declarative schema definitions for entity compliance validation.
+
+A schema describes the expected structure of an entity: which sections
+are required, word count bounds, heading format, and valid enum values.
+Schemas are frozen (immutable once created).
+"""
+
+from dataclasses import dataclass
+from enum import Enum
+from typing import Optional, Tuple
+
+
+class SectionRequirement(Enum):
+    """How strictly a section must be present."""
+
+    REQUIRED = "required"
+    RECOMMENDED = "recommended"
+    OPTIONAL = "optional"
+
+
+@dataclass(frozen=True)
+class SectionRule:
+    """Validation rule for a single H2 section.
+
+    Parameters
+    ----------
+    slug:
+        Section slug as it appears in entity metadata (e.g. ``definition``).
+    label:
+        Human-readable section name for diagnostics.
+    requirement:
+        Whether the section is required, recommended, or optional.
+    min_words:
+        Minimum word count (inclusive).  ``None`` means no lower bound.
+    max_words:
+        Maximum word count (inclusive).  ``None`` means no upper bound.
+    """
+
+    slug: str
+    label: str
+    requirement: SectionRequirement
+    min_words: Optional[int] = None
+    max_words: Optional[int] = None
+
+
+@dataclass(frozen=True)
+class EnumConstraint:
+    """Constraint limiting a field to a set of allowed values.
+
+    Parameters
+    ----------
+    field_name:
+        The ``EntityMeta`` field to check (e.g. ``domain``).
+    allowed_values:
+        Tuple of acceptable string values.
+    severity:
+        ``"error"`` or ``"warning"`` when the value is not in the set.
+    """
+
+    field_name: str
+    allowed_values: Tuple[str, ...]
+    severity: str = "warning"
+
+
+@dataclass(frozen=True)
+class EntitySchema:
+    """Complete validation schema for an entity type.
+
+    Parameters
+    ----------
+    name:
+        Human-readable schema name (e.g. ``"Economic Entity"``).
+    section_rules:
+        Tuple of :class:`SectionRule` objects.
+    enum_constraints:
+        Tuple of :class:`EnumConstraint` objects.
+    h1_title_case_severity:
+        Severity for non-title-case H1 headings (``"error"`` or ``"warning"``).
+    require_h1:
+        Whether a non-empty slug (H1) is required.
+    """
+
+    name: str
+    section_rules: Tuple[SectionRule, ...]
+    enum_constraints: Tuple[EnumConstraint, ...] = ()
+    h1_title_case_severity: str = "warning"
+    require_h1: bool = True
+
+
+# ── Default schema for the economic-entity infospace ──────────────
+
+ECONOMIC_ENTITY_SCHEMA = EntitySchema(
+    name="Economic Entity",
+    section_rules=(
+        SectionRule(
+            slug="definition",
+            label="Definition",
+            requirement=SectionRequirement.REQUIRED,
+            min_words=20,
+            max_words=150,
+        ),
+        SectionRule(
+            slug="source_chapter",
+            label="Source Chapter",
+            requirement=SectionRequirement.REQUIRED,
+        ),
+        SectionRule(
+            slug="context",
+            label="Context",
+            requirement=SectionRequirement.REQUIRED,
+        ),
+        SectionRule(
+            slug="economic_domain",
+            label="Economic Domain",
+            requirement=SectionRequirement.REQUIRED,
+        ),
+        SectionRule(
+            slug="smith_s_original_wording",
+            label="Smith's Original Wording",
+            requirement=SectionRequirement.OPTIONAL,
+        ),
+        SectionRule(
+            slug="modern_interpretation",
+            label="Modern Interpretation",
+            requirement=SectionRequirement.OPTIONAL,
+        ),
+    ),
+    enum_constraints=(
+        EnumConstraint(
+            field_name="domain",
+            allowed_values=(
+                "Production",
+                "Exchange",
+                "Distribution",
+                "Regulation",
+                "General Theory",
+            ),
+            severity="warning",
+        ),
+    ),
+    h1_title_case_severity="warning",
+    require_h1=True,
+)