Center from evidence.
Not from habit.

RadialHubRootBundle {
  schema,          // Compo23.00 RadialSystemSchema
  seed,            // exact schema ref
  subjectSet,      // exact subject set
  frameBinding,    // exact 2D frame
  positionBindings // exact one per subject
}

23.01 validates refs from 23.00.
It does not reconstruct or rewrite root identity.

23.00 stores binding refs in the schema; 23.01 therefore consumes the exact records alongside the schema and validates their canonical refs.

RadialPositionObservation {
  scopeRef, snapshotRef, subjectRef,
  coordinateFrameRef,
  positionRef, positionOwnerRef,
  x, y, unitRef,
  sourceRef, sourceOwnerRef,
  provenance, status,
  mutationAllowed: false
}

RadialHubDetectionPolicy {
  candidateSelectionMode: EXPLICIT_EVIDENCE_ONLY,
  conflictResolutionMode: EXACT_COORDINATE_CONSENSUS_ONLY,
  maxEvidence: 0..128,
  maxCandidates: 1..128,
  maxPositionObservations: 0..4096,
  overflowMode: N_A_WITHOUT_TRUNCATION,
  allowArithmeticMeanCandidate: false,
  autoFrameCenterCandidate: false,
  autoVisualCentroidCandidate: false,
  autoTolerance: false,
  autoScoring: false
}

No Cartesian product, no random seed, no silent truncation. Repeated evidence identity is rejected; distinct evidence may support the same exact point.

RadialHubDescriptor {
  radialSystemRef,
  scopeRef, snapshotRef,
  coordinateFrameRef, unitRef,
  x, y,
  supportingHubSubjectRefs[],
  sourceCandidateRefs[],
  basisKinds[],
  heuristicCandidateUsed,
  provenanceSet[],
  status,
  mutationAllowed: false
}

RadialHubAttachment {
  radialSystemSeedRef,
  hubDescriptorRef,
  status,
  mutationAllowed: false
}

Compo23.00 RadialSystemSeed.hubAttachmentRef
remains unchanged in-place.

Tests cover exact 23.00 lineage, numeric coordinate adapters, explicit evidence kinds, declared-subject resolution, optional mean heuristic, exact consensus/conflict preservation, zero coordinates, immutable attachment, zero metrics, Topic22 firewall and strict 23.02–23.04 ownership boundaries.

{
  "module": "Compo 23.01",
  "name": "hub_center_detection",
  "version": "1.0-canonical",
  "canonical_main_title": "Hub/center detection",
  "topic": "23_РАДИАЛЬНЫЙ_БАЛАНС_И_ЦЕНТРАЛЬНЫЕ_СИСТЕМЫ",
  "scope": "EXACT_RADIAL_ROOT_LINEAGE_OWNER_QUALIFIED_POSITION_OBSERVATIONS_EXPLICIT_HUB_EVIDENCE_OPTIONAL_EXPLICITLY_ENABLED_ARITHMETIC_MEAN_CANDIDATE_EXACT_CENTER_CONSENSUS_AND_IMMUTABLE_HUB_ATTACHMENT_ONLY",
  "main_topic_contract": {
    "topic_title": "Радиальный баланс и центральные системы",
    "topic_goal": "Формализует радиальные композиции: hub, rings, radius bands, angular sectors и распределение элементов вокруг центра.",
    "expected_output": "RadialGroupDescriptor, hub, rings, sectors",
    "planned_files": [
      "23.00 Radial system schema",
      "23.01 Hub/center detection",
      "23.02 Radius bands and orbital groups",
      "23.03 Angular spacing / sector occupancy",
      "23.04 Scoring, generator and tests"
    ]
  },
  "ownership": {
    "owner": "Compo23.01",
    "owns": [
      "RadialPositionObservation adapter",
      "RadialHubEvidenceKind taxonomy",
      "RadialHubEvidence",
      "RadialHubCandidateKind taxonomy",
      "RadialHubCandidate",
      "RadialHubDetectionPolicy",
      "RadialHubCandidateSet",
      "RadialHubResolution",
      "RadialHubDescriptor",
      "RadialHubAttachment",
      "exact hub-point consensus resolution",
      "optional explicitly-enabled arithmetic-mean-of-member-positions center candidate",
      "identity/status/provenance rules for Topic23 hub layer",
      "non-mutating correction request for hub/position evidence"
    ],
    "does_not_own": [
      "RadialSystemSchema / RadialSystemSeed identity — Compo23.00",
      "raw point geometry or foreign position identities — upstream geometry owners",
      "visual center of mass / mass weighting / moments — Topic22",
      "polar radius, rings, radius bands, orbital groups — Compo23.02",
      "polar angle, angular spacing, sector occupancy — Compo23.03",
      "approximation tolerance, target fit, scoring, MetricResult or layout candidate generator — Compo23.04",
      "symmetric balance / mirror correspondence — Topic21",
      "dominance / hierarchy / semantic importance / beautyScore / final-layout ranking",
      "foreign geometry/style/semantic mutation"
    ]
  },
  "consumes": [
    "exact Compo23.00 root bundle: RadialSystemSchema, RadialSystemSeed, RadialSubjectSet, RadialCoordinateFrameBinding, RadialPositionBinding[]",
    "owner-qualified numeric position observations resolving exact foreign positionRef values",
    "explicit hub evidence: EXPLICIT_COORDINATE or DECLARED_SUBJECT_POSITION",
    "optional explicit policy enabling arithmetic-mean center candidate"
  ],
  "provides": [
    "RadialPositionObservation[]",
    "RadialHubEvidence[]",
    "RadialHubCandidateSet",
    "RadialHubResolution",
    "RadialHubDescriptor",
    "RadialHubAttachment"
  ],
  "owns_metrics": [],
  "independent_numeric_votes": 0,
  "status_semantics": {
    "OK": "valid exact local hub resolution or valid record",
    "N_A": "missing/conflicting/not-applicable evidence; never numeric zero",
    "INVALID": "malformed or impossible record; never numeric zero"
  },
  "hub_evidence_kinds": [
    "EXPLICIT_COORDINATE",
    "DECLARED_SUBJECT_POSITION"
  ],
  "hub_candidate_kinds": [
    "EXPLICIT_COORDINATE",
    "DECLARED_SUBJECT_POSITION",
    "ARITHMETIC_MEAN_MEMBER_POSITIONS"
  ],
  "policy": {
    "candidateSelectionMode": "EXPLICIT_EVIDENCE_ONLY by default",
    "conflictResolutionMode": "EXACT_COORDINATE_CONSENSUS_ONLY",
    "maxEvidence": [
      0,
      128
    ],
    "maxCandidates": [
      1,
      128
    ],
    "maxPositionObservations": [
      0,
      4096
    ],
    "overflow": "N_A_WITHOUT_TRUNCATION",
    "allowArithmeticMeanCandidate": false,
    "autoFrameCenterCandidate": false,
    "autoVisualCentroidCandidate": false,
    "autoTolerance": false,
    "autoScoring": false
  },
  "resolution_rules": [
    "one valid candidate -> exact local hub point",
    "multiple candidates with exactly equal x/y -> exact consensus hub point",
    "multiple candidates with different x/y -> N_A; confidence/source order does not select a winner",
    "no valid candidates -> N_A",
    "invalid selected evidence/observation -> INVALID",
    "arithmetic mean is an IMPLEMENTATION_HEURISTIC and exists only when explicitly enabled"
  ],
  "root_attachment_contract": {
    "radialSystemSeedRef": "exact Compo23.00 seed lineage",
    "hubDescriptorRef": "exact Compo23.01 descriptor identity",
    "rootMutation": false,
    "metricResultRefs": []
  },
  "firewalls": [
    "coordinate-frame origin != hub",
    "frame center != hub",
    "viewport center != hub",
    "unweighted arithmetic mean candidate != Topic22 visual center of mass",
    "arithmetic mean candidate != truth and is disabled by default",
    "hub point != focal point",
    "hub point != semantic importance",
    "hub subject != hierarchy role",
    "hub subject != required content",
    "hub resolution != ring membership",
    "hub resolution != sector membership",
    "exact coordinate conflict != approximate agreement",
    "confidence != conflict winner",
    "source order != priority",
    "N_A != 0",
    "INVALID != 0",
    "descriptor != score",
    "heuristic != law",
    "local != global",
    "geometry != interpretation"
  ],
  "topic23ProgressAfterThisModule": "2/5 local",
  "next_module": "Compo 23.02 — Radius bands and orbital groups",
  "hard_stop": "No 23.02–23.04 implementation in this file"
}