feat: add Composer Arena public preview

package.json

@@ -3,7 +3,8 @@
   "version": "0.1.0",
   "private": true,
   "scripts": {
-    "check:bench": "node scripts/check-bench-route.mjs",
+    "check:arena": "node scripts/check-composer-arena.mjs",
+    "check:bench": "node scripts/check-bench-route.mjs && node scripts/check-composer-arena.mjs",
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
@@ -21,6 +22,7 @@
     "@types/node": "^20",
     "@types/react": "^19",
     "@types/react-dom": "^19",
+    "ajv": "^8.17.1",
     "eslint": "^9",
     "eslint-config-next": "16.1.6",
     "tailwindcss": "^4",

public/bench/composer-arena/evidence/pilot/2026-07-19/README.md

@@ -0,0 +1,14 @@
+# Composer Arena seven-family task-success evidence — 2026-07-19
+
+This is a sanitized deterministic-evidence aggregate over seven eligible FineVideo public-eval cells from seven distinct source families. It is not a leaderboard, preference result, or publication approval.
+
+The public packet reports only cohort counts and stable evidence hashes:
+
+- mechanical control: 6/7 structural passes and 5/7 complete outputs accepted;
+- evaluated lane A: 2/7 complete outputs accepted;
+- evaluated lane B: 4/7 complete outputs accepted;
+- zero blind battles, votes, ranks, or winner.
+
+Evaluated model identities remain sealed pending the founder's blind vote. The real blind packet, candidate media, per-cell identifiers, output hashes, prompts, run identifiers, private paths, and identity mapping are not included here.
+
+Deterministic task success and complete-output acceptance do not measure editorial preference. SEA Broadcast ASR remains a separate benchmark suite with independent sources, rights, scoring, and publication gates.

public/bench/composer-arena/evidence/pilot/2026-07-19/checksums.json

@@ -0,0 +1,8 @@
+{
+  "algorithm": "sha256",
+  "files": {
+    "seven-family-results.json": "ed2cba9fb604a7d2db70b862fd760c5287e55b21d3b4cc6aeb8415285fa57d1f",
+    "seven-family-results.schema.json": "a26f151cb7102294f8e7a0712031bd6a2462b1561568901edc37f97e586bade3",
+    "README.md": "0630d7415cded4039c6fde74101610a6b746cd0556fa78807c5e2fff51b6a61a"
+  }
+}

public/bench/composer-arena/evidence/pilot/2026-07-19/seven-family-results.json

@@ -0,0 +1,93 @@
+{
+  "schema_version": 1,
+  "evidence_id": "composer-arena-seven-family-task-success-2026-07-19",
+  "evidence_date": "2026-07-19",
+  "status": "seven-family-terminal-task-success-publication-not-approved",
+  "data_class": "sanitized_task_success_aggregate",
+  "publication": {
+    "surface": "evidence/pilot",
+    "publishable": false,
+    "state": "insufficient_evidence",
+    "leaderboard": false,
+    "winner": null,
+    "rank_count": 0,
+    "human_preference_claims": false
+  },
+  "vote_provenance": {
+    "collection_mode": "no_eligible_votes",
+    "crowdsourced": false,
+    "blind_battles": 0,
+    "real_human_votes": 0,
+    "resolved_battle_groups": 0
+  },
+  "frozen_evidence": {
+    "dataset_repo_id": "HuggingFaceFV/finevideo",
+    "dataset_revision": "84c74091e1c6ee7a5dffabfafb5c9033e4718883",
+    "staging_manifest_sha256": "0b395b961b0de0bb6a5c54ff80b13582d23f8e3d2e729aa7e950b1df8536d2b8",
+    "contract_sha256": "33ca2f1b72ee9def3bd039eda69d9903ec595d860936a0353fdb045576215624",
+    "release_sha256": "d37cd450934c49721cb75de14353e070759c8220f1ed87567799473e8ab88926",
+    "case_pack_sha256": "74356b45867f492688e25a10c6e13a6fa2848f41ce00aa025d83adb7639ce203"
+  },
+  "cohort": {
+    "eligible_cells": 7,
+    "distinct_source_families": 7,
+    "favorable_selection": false,
+    "source_family_disjoint": true
+  },
+  "task_success": {
+    "separation_statement": "Deterministic task success and complete-output acceptance are system evidence only; they never create a preference score, rank, or winner.",
+    "lanes": [
+      {
+        "lane_id": "mechanical-control",
+        "classification": "control",
+        "identity_state": "public_control",
+        "attempted_cells": 7,
+        "structural_passes": 6,
+        "structural_failures": 1,
+        "complete_outputs_accepted": 5,
+        "complete_output_failures": 2,
+        "model_calls": 0,
+        "source_summary_sha256": "3b856b8f1947b30da495b3a2fce20074270777d1f09b67b574dc318133291c57"
+      },
+      {
+        "lane_id": "evaluated-lane-a",
+        "classification": "evaluated_system",
+        "identity_state": "sealed_pending_founder_vote",
+        "attempted_cells": 7,
+        "structural_passes": 2,
+        "structural_failures": 5,
+        "complete_outputs_accepted": 2,
+        "complete_output_failures": 5,
+        "model_calls": 7,
+        "source_summary_sha256": "7505dd209740beb4c5696d778982de105996a01f53043ab550ce5888ae8efa1a"
+      },
+      {
+        "lane_id": "evaluated-lane-b",
+        "classification": "evaluated_system",
+        "identity_state": "sealed_pending_founder_vote",
+        "attempted_cells": 7,
+        "structural_passes": 4,
+        "structural_failures": 3,
+        "complete_outputs_accepted": 4,
+        "complete_output_failures": 3,
+        "model_calls": 7,
+        "source_summary_sha256": "adde8ddfb024bc1b1993ddc0ad72c79bfc362099c49ad6045bde9e0b1e22f456"
+      }
+    ]
+  },
+  "blind_review": {
+    "packet_public": false,
+    "candidate_outputs_public": false,
+    "identity_mapping_public": false,
+    "founder_vote_recorded": false,
+    "next_gate": "founder_blind_vote_then_separate_identity_reveal"
+  },
+  "limitations": [
+    "Evaluated lane identities are deliberately sealed until the founder records the blind vote.",
+    "The public aggregate contains no per-cell identifiers, output hashes, candidate media, prompts, run identifiers, or identity mapping.",
+    "Complete-output acceptance measures deterministic delivery gates, not editorial quality or human preference.",
+    "The controlled-agent track remains blocked because the released evidence pack contains no transcript, OCR, or semantic events.",
+    "One mechanical-control cell failed structurally and one rendered control output failed the opening-black gate; neither failure was repaired inside the frozen cohort.",
+    "No official ranking, winner, governed vote backend, or public blind packet exists."
+  ]
+}