Event admission gate: an unresolved or contradicted game does not earn a Read

A fractured identity keeps two bad records from merging. It does not make an
unknown game true. Until now a prop with an unresolved or verified-impossible
event still continued into grading under that synthetic key; it no longer does.

- event_binding_status contract: RESOLVED / UNRESOLVED / AMBIGUOUS /
  CONTRADICTED / UNSUPPORTED. CONTRADICTED and UNRESOLVED stay distinct — one
  means we know the association is wrong, the other that we do not know.
- ONE admission gate (gradeSlateService.admitForGrading), before dedupe and
  before grading. Admission requires RESOLVED *and* a canonical_event_id; a
  legacy derived game_id can never satisfy it. Rejected props are returned, not
  discarded, so retention keeps them as evidence.
- Roster evidence is now DATE-SCOPED. statsapi honours ?date= and it changes the
  answer (Joe Mack is on the 2026-08-26 Marlins roster, absent on 2026-04-15).
  Evidence that does not describe the slate's date can only yield UNRESOLVED,
  never CONTRADICTED — uncertainty must not become an accusation.
- A mis-nested market is REFUSED, never re-bound. Knowing Joe Mack is a Marlin
  does not license moving a provider record into the Marlins game; that would
  invent provenance.

Measured on the real 2026-08-26 slate: 2,878 props -> 2,874 admitted, 4 rejected
(EVENT_PLAYER_TEAM_CONTRADICTION), each player's correct game still resolving.
Doubleheader 824514/824478 both remain independently RESOLVED and admitted.

No change to probability, projection, side, grade, confidence, ranking,
normalization or calibration. Lineage remains disabled.

Suite 380/5,061/0 from the release worktree; web tsc exit 0.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CQJeAG8vcDoL5zkiaJyVb8

scripts/dedupe-parity.js

@@ -65,12 +65,15 @@ async function main() {
 
   // PARTICIPANT EVIDENCE — the same index production builds.
   const built = await E.buildPlayerTeamIndex(games, {
-    getTeamRoster: async (id) => {
-      const r = await (await fetch(`https://statsapi.mlb.com/api/v1/teams/${id}/roster?rosterType=active`)).json();
+    asOfDate: DATE,
+    getTeamRoster: async (id, asOf) => {
+      const d = asOf ? `&date=${asOf}` : '';
+      const r = await (await fetch(`https://statsapi.mlb.com/api/v1/teams/${id}/roster?rosterType=active${d}`)).json();
       return (r.roster || []).map((x) => ({ id: x.person && x.person.id, name: x.person && x.person.fullName }));
     },
   });
   const playerTeams = built.index;
+  const evidenceDateValid = E.evidenceIsDateValid(built.stats, DATE);
 
   // Reconstruct prop shapes. One row per (player, stat, line, book) — the side
   // is not part of the dedupe key, so both sides collapse to the same prop.
@@ -92,7 +95,7 @@ async function main() {
   }
   // The schedule has one game per pair on a non-doubleheader date, so teams
   // alone resolve; no game_time is needed and none is reconstructed.
-  const ident = E.attachEventIdentity(SPORT, props, games, playerTeams);
+  const ident = E.attachEventIdentity(SPORT, props, games, playerTeams, evidenceDateValid);
 
   const oldSet = new Set(props.map(oldKey));
   const newSet = new Set(props.map(newKey));
@@ -112,7 +115,11 @@ async function main() {
   console.log(`participant evidence          : ${built.stats.players} players / ${built.stats.teams} rosters`);
   console.log(`canonical event resolution    : ${ident.canonical}/${ident.total}`
     + ` (unresolved ${ident.unresolved}, unsupported ${ident.unsupported})`);
-  console.log(`IMPOSSIBLE-BINDING refusals   : ${ident.impossible}`);
+  console.log(`evidence date-valid           : ${evidenceDateValid} (as of ${DATE})`);
+  console.log(`CONTRADICTED bindings         : ${ident.impossible}`);
+  const gate = require('../src/services/gradeSlateService').__internals.admitForGrading(props, SPORT);
+  console.log(`ADMITTED to grading           : ${gate.admitted.length}`);
+  console.log(`REJECTED before grading       : ${gate.rejected.length} ${JSON.stringify(gate.reasons)}`);
   if (Object.keys(ident.reasons).length) console.log(`  unresolved reasons          : ${JSON.stringify(ident.reasons)}`);
   console.log(`distinct events               : ${new Set(props.map((p) => p.canonical_event_id).filter(Boolean)).size}`);
   console.log('');