/**
 * One fixed, closed census of the Skills database maintenance surface.
 *
 * Why it exists (I6-00024): a production migration is held until the exact
 * current registry, version ledger and migration ledger are read from the live
 * database. The enrollment inspection answers a different question (one
 * operator key), and no existing reader returns the fixed aggregate + ledger
 * census. This module is that reader, and it is deliberately shaped so it
 * cannot become a general SQL console:
 *
 *   - No target, query, schema or table input exists. The only argument is the
 *     database URL, and the operation refuses to run unless the connection
 *     resolves to the fixed public schema the Skills store uses.
 *   - Every owned-table read is schema-qualified to `public`. A connection whose
 *     search path falls through to a later schema cannot substitute another
 *     schema's tables: a missing public table refuses (CENSUS_SCHEMA_UNAVAILABLE)
 *     instead of counting rows that do not belong to the fixed target.
 *   - The transaction is READ ONLY, REPEATABLE READ, with a five-second
 *     statement timeout and a one-second lock timeout, asserted from inside the
 *     read path rather than assumed.
 *   - The output is a closed shape with per-field size bounds, a bounded
 *     migration ledger and a total serialized-size gate. Nothing is truncated
 *     silently: a census that would exceed a bound refuses instead.
 *   - Nothing imports the application store: no initialization, migrations,
 *     backfills or writes happen on this path.
 */
export interface SchemaCensusResult {
    status: "inspected";
    database: string;
    role: string;
    serverVersion: string;
    schema: "public";
    transaction: {
        readOnly: true;
        isolation: "repeatable read";
        statementTimeoutMs: number;
        lockTimeoutMs: number;
    };
    migrations: {
        count: number;
        versions: string[];
    };
    registry: {
        rows: number;
    };
    versions: {
        rows: number;
    };
    lifecycle: {
        active: {
            live: number;
            tombstoned: number;
        };
        archived: {
            live: number;
            tombstoned: number;
        };
    };
    authorizationEpoch: {
        exists: false;
    } | {
        exists: true;
        nullCount: number;
    };
}
type CensusCode = "CENSUS_POSTGRES_REQUIRED" | "CENSUS_SCHEMA_UNAVAILABLE" | "CENSUS_ACCESS_DENIED" | "CENSUS_WRITE_REFUSED" | "CENSUS_TIMEOUT" | "CENSUS_CONNECTION_FAILED" | "CENSUS_TARGET_MISMATCH" | "CENSUS_INVALID_RESULT" | "CENSUS_OUTPUT_UNBOUNDED" | "CENSUS_FAILED";
export declare class SchemaCensusError extends Error {
    readonly code: CensusCode;
    constructor(code: CensusCode);
}
/**
 * Census metadata only. Deliberately does not import or initialize the application store.
 *
 * @param databaseUrl explicit PostgreSQL URL; there is no implicit localhost fallback.
 */
export declare function inspectSchemaCensus(databaseUrl: string): Promise<SchemaCensusResult>;
export {};