fix(server): repair the initial-connect outbox envelope and unblock dispatch

ApplyInitialConnectPlan wrote a payload of {match_id,state,action},
omitting event, revision, resource_id, occurred_at and player_ids --
every field deliverStateOutboxEvent requires. Delivery rejected the row,
dispatch returned on the first error so it was never acknowledged, and
because reads are ordered oldest-first it was retried ahead of every
later state_changed event on every 100ms poll. One initial-connect
transition therefore blocked lifecycle delivery for all matches, not
just its own.

Two independent fixes, since either alone leaves the system fragile:

Build envelopes through one validating helper (MarshalOutboxEnvelope)
and convert all five writers to it. A writer that omits a required
field now fails its own transaction instead of committing a row that
can only ever poison the queue. The helper takes revision as int64 so
the -1 "nothing matched" sentinel some CTEs return surfaces as an error
rather than wrapping to a huge uint64.

Make dispatch resilient regardless: a delivery failure is now counted
against that row and the batch continues, with the row dead-lettered
after MaxOutboxDeliveryAttempts so a poison event degrades to one lost
notification instead of a stalled queue. Ordering within an aggregate
is still honoured -- later events of a failed match are deferred, so no
client observes that match's newer state before its older state. An ack
failure still stops the batch, being a database rather than a payload
problem.

Initial-connect events now address every participant, not just the
connected ones: a no-show needs to learn their ticket was failed and a
penalty applied.

server/store/postgres_integration_test.go

@@ -1792,8 +1792,11 @@ func TestPostgreSQLMigrationsRollBackAndReapplyCleanly(t *testing.T) {
 	// Roll back every migration one at a time, in reverse, checking each
 	// down file actually undoes what its forward file created — not just
 	// that Rollback returns nil.
-	if err := migrations.Rollback(context.Background(), db, dir, 7); err != nil {
-		t.Fatalf("rollback 0013 through 0007: %v", err)
+	// This count is the number of migrations above 0006, so it must grow with
+	// every new migration; otherwise the later fixed-count rollbacks below
+	// silently target the wrong files.
+	if err := migrations.Rollback(context.Background(), db, dir, 8); err != nil {
+		t.Fatalf("rollback 0014 through 0007: %v", err)
 	}
 	var hasInitialConnectReadyColumn bool
 	if err := db.QueryRow(`SELECT count(*) > 0 FROM information_schema.columns WHERE table_name = 'matches' AND column_name = 'initial_connect_ready_at'`).Scan(&hasInitialConnectReadyColumn); err != nil {