refactor: eliminate remaining hardcoded predicate-name dispatch

Extraction.ts (3 fixes):
  - Replace 2 'inStackingContext' string checks with isVariableArityPredicate()
  - Replace 7-name diagnostic formatting if/else with spec-driven
    getPredicateSpec() checks (isDirectional → gap message,
    isSize → threshold hint, else generic)

Grammar.ts: Replace 8 hardcoded parser routing checks
  (atLeast/atMost/aspectRatio/between/clippedBy/attachedToScrollContainer/
  escapeClippingChainOf/inStackingContext) with SIZE_PREDICATE_NAMES and
  TOPOLOGY_PREDICATE_NAMES Sets derived from spec table.

Pipeline.ts: Replace 15-entry CODE_TO_CLAUSE_KIND map with runtime
  generation from PREDICATE_SPECS. Prefix derived from spec.isSize
  ('size.*') / validOptions.includes('axis') ('alignment.*') /
  else ('relation.*'). Manual override for aspectRatio code 15.

Proofs.ts: Replace 11-case switch(kind) with 5 spec-driven if/else
  branches categorized by validOptions presence (hasGap→directional,
  hasAxis→alignment) + 2 specific name checks (inside overflow,
  aspectRatio ratio). 11 predicate names → 0 hardcoded.

Lexer.ts: Export KEYWORDS map for conformance testing.

Conformance tests:
  - Solver: every BUILTIN_PREDICATES entry matches its PREDICATE_SPECS
    counterpart; every spec name (incl. aliases) has a registered
    evaluator with matching descriptor (2 tests)
  - DSL: every predicate name from collectAllPredicateNames() appears
    in the lexer KEYWORDS table (1 test)

598 SDK + 3 conformance + 57 E2E = 658 tests pass.

packages/imhotep-core/src/pipeline.ts

@@ -106,6 +106,7 @@ import type {
 } from './diagnostics.js'
 
 import { createDiagnostic } from './diagnostics.js'
+import { PREDICATE_SPECS } from './predicate-specs.js'
 
 // Adapter interfaces - implementations injected at runtime
 interface ExtractorRequest {
@@ -433,25 +434,23 @@ export interface PipelineResult {
 
 /**
  * Reverse mapping from execution IR clause type codes to solver clause kinds.
- * Mirrors the relationCodes table in imhotep-dsl/compiler.ts.
+ * Built from the predicate spec table — any predicate with a relationCode
+ * automatically gets a clause kind entry.
  */
-const CODE_TO_CLAUSE_KIND: Record<number, string> = {
-  1: 'relation.leftOf',
-  2: 'relation.rightOf',
-  3: 'relation.above',
-  4: 'relation.below',
-  5: 'alignment.alignedWith',
-  6: 'alignment.leftAlignedWith',
-  7: 'alignment.rightAlignedWith',
-  8: 'alignment.topAlignedWith',
-  9: 'alignment.bottomAlignedWith',
-  10: 'alignment.centeredWithin',
-  11: 'relation.inside',
-  12: 'relation.contains',
-  13: 'relation.overlaps',
-  14: 'relation.separatedFrom',
-  15: 'size.aspectRatio',
-}
+const CODE_TO_CLAUSE_KIND: Record<number, string> = (() => {
+  const map: Record<number, string> = {}
+  for (const spec of PREDICATE_SPECS) {
+    if (!spec.relationCode) continue
+    let prefix = 'relation'
+    if (spec.isSize) prefix = 'size'
+    else if (spec.validOptions.includes('axis')) prefix = 'alignment'
+    map[spec.relationCode] = `${prefix}.${spec.name}`
+  }
+  return map
+})()
+// DSL keyword 'aspectRatioBetween' uses code 15; maps to the canonical
+// 'aspectRatio' predicate which has no separate relationCode.
+CODE_TO_CLAUSE_KIND[15] = 'size.aspectRatio'
 
 // ---------------------------------------------------------------------------
 // Main Pipeline Orchestrator