refactor: complete rolling-hash rollout — composite/srcRel/dstRel keys + key-tracked cache invalidation

Completes the rolling-hash rollout (previously only createChainKey hashed):
- createCompositeKey, createSrcRelKey, createDstRelKey, and the
  valueRelationsBySrc/Dst keys now produce 53-bit rolling hashes instead of
  `src|rel|dst` string concatenation. Direction markers keep srcRel vs dstRel
  distinct; the composite/chain keys are exact integers usable as Map keys.
- Direct-check cache invalidation is now key-TRACKED instead of pattern-
  matched: every direct-check result is registered under the checked relation,
  its base relations (reverse dependency index), and the subject/object node
  ids (Arbiter._trackDirectCheckKey). Relation-level invalidation deletes the
  tracked keys for each affected relation (covering config-override checks);
  node-level invalidation (node removal / updateNodeData) deletes by node id.
  This replaces the pipe-delimited-string regex matching that required the old
  key format.
- DecisionCache.invalidateByNodeKey and invalidateAll route through the tracked
  indexes; tracking maps are cleared on full flush.

Tests updated to the tracked contract (register injected keys via
_trackDirectCheckKey); full suite green.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@arbiter/core",
-  "version": "1.0.5",
+  "version": "1.0.6",
   "description": "Arbiter core engine: graph indices, relation/reachability, authorization rule evaluator, DSL/AST, condensed & sharded snapshots, and evidence fusion.",
   "license": "ISC",
   "author": "",