fix: add error logging to access control catch block

[gugli4ifenix-design]

Problem

checkUniqueItemExists in access-control.ts has an empty catch block (line 431) that silently swallows all errors from findOne:

try {
    const item = await context.db[foreignList.listKey].findOne({ where: uniqueInput })
    if (item !== null) return uniqueWhere
} catch (err) {} // <- all errors silently swallowed

If findOne fails for any reason (DB connection error, misconfiguration, schema mismatch), the error is invisible — making access control issues extremely hard to debug in development.

Fix

Add console.warn in non-production environments:

} catch (err) {
    if (process.env.NODE_ENV !== 'production') {
        console.warn(\`[keystone] access-control: findOne failed for ${foreignList.listKey}:\`, err)
    }
}

• Behavior unchanged — access is still denied on error
• Development visibility — errors are now logged for debugging
• Production safe — no logging in production (opt-in only)

Found during a static analysis sweep of 97 popular open source projects.