Fix AUTOINCREMENT not populating identity columns in IndexedDB tables

[Copilot]

AUTOINCREMENT (mapped to IDENTITY) columns were silently dropped when inserting into IndexedDB-backed tables — the column was absent entirely from query results rather than receiving an auto-incremented value.

Root cause

IDB.intoTable passed records directly to IndexedDB without applying the table's identities counter, bypassing the logic that both the in-memory table.insert path and LS.intoTable (LocalStorage) already handle.

Changes

• src/91indexeddb.js — IDB.intoTable: Before writing records to the object store, iterate table.identities and assign the current counter value to any record missing that column, then advance the counter (or sync it forward if the user supplied an explicit value ≥ the current counter).

// Before: records inserted as-is, identity column absent
tb.add(value[i]);

// After: identity values applied, counter advanced per record
if (!userProvided) value[i][columnid] = ident.value;
if (userProvided && +value[i][columnid] >= ident.value) {
    ident.value = +value[i][columnid] + ident.step;
} else {
    ident.value += ident.step;
}

• test/test861.js: Browser-only tests verifying AUTOINCREMENT values are populated on insert and continue incrementing across multiple INSERT statements.

• Fixes AUTOINCREMENT for INDEXEDDB does not seem to work #861