/**
 * Assert the schema-residency invariant that nexus silently depends on.
 *
 * ## The invariant nobody wrote down (gh#1298 · gh#1283)
 *
 * `ensureGlobalRegistryAttached()` ATTACHes the global `cleo.db` onto the
 * PROJECT handle as `nexus_global`, so that nexus registry tables resolve by
 * their BARE names through SQLite's fall-through. Its own comment states the
 * split:
 *
 *   > graph tables resolve to the project `main`; registry/identity tables fall
 *   > through to the attach.
 *
 * That split is correct **only while each bare name exists in exactly one of the
 * two schemas.** SQLite resolves an unqualified name by searching `temp`, then
 * `main`, then attached schemas in attach order — so a table present in BOTH is
 * answered by `main` with no error and no cue. Nexus is therefore correct today
 * **by resolution order, not by the invariant it documents**, and nothing fails
 * if that stops being true.
 *
 * ## It is already half-false
 *
 * ADR-090 / T11538 moved the four code-graph tables (`nexus_nodes`,
 * `nexus_relations`, `nexus_contracts`, `nexus_code_index`) into the project
 * scope, and T11539 removed them from the global schema source. **No migration
 * drops them from a database that already has them** — removing a table from a
 * schema module does not remove it from disk. So a global `cleo.db` created
 * before that change still carries all four, at 0 rows, shadowing the populated
 * project copies.
 *
 * Measured 2026-09-12: project `nexus_nodes` = 26,964 and `nexus_relations` =
 * 75,500; the global copies are present and empty. Today the right side wins
 * because `main` is the project. If anything ever reads them from a handle
 * whose `main` is the GLOBAL store, it gets **0 rows — an empty graph,
 * indistinguishable from "nothing has been indexed yet"**, which is precisely
 * the symptom this project has already lost a session to.
 *
 * ## Why this reports rather than repairs
 *
 * A blind `DROP TABLE` would be wrong. This install's global copies are empty,
 * but an install that used nexus BEFORE the residency move wrote its graph
 * rows to the global store, and no migration relocated them. There, the four
 * tables may hold the only copy. Dropping on the strength of one machine's
 * measurement is the same error as inferring a rule from the rows it is then
 * used to exempt.
 *
 * So this scan reports `safeToDrop` per table, and only ever for an EMPTY one.
 * A populated orphan is a data-migration question for the owner, not a cleanup.
 *
 * @task T12158
 * @see ADR-090 §2.1 — nexus graph residency
 * @see ADR-092 — failure geometries
 */
/**
 * Tables nexus resolves by BARE name through the `nexus_global` attach.
 *
 * Each MUST exist in exactly one of the two schemas. Sourced from
 * `schema/cleo-global/nexus.ts`, which is their only declaration.
 */
export declare const NEXUS_FALLTHROUGH_TABLES: readonly ["nexus_audit_log", "nexus_devices", "nexus_project_git_state", "nexus_project_id_aliases", "nexus_project_locations", "nexus_project_paths", "nexus_project_registry", "nexus_sigils", "nexus_user_profile"];
/**
 * Code-graph tables that moved to the project scope under ADR-090 / T11538.
 *
 * They must NOT be present in the global store. Any that are, are orphans left
 * by a schema removal that never became a migration.
 */
export declare const NEXUS_PROJECT_GRAPH_TABLES: readonly ["nexus_code_index", "nexus_contracts", "nexus_nodes", "nexus_relations"];
/** One table that is resident where it should not be. */
export interface NexusResidencyFinding {
    /** The table name. */
    readonly table: string;
    /** What is wrong with where it lives. */
    readonly kind: 'orphaned-in-global' | 'ambiguous-fallthrough';
    /** Rows in the offending copy. */
    readonly rows: number;
    /**
     * Whether removing the offending copy is provably lossless.
     *
     * Only ever `true` for an empty table. A populated orphan may hold the only
     * copy on an install that predates the residency move, so it is a migration
     * question rather than a cleanup.
     */
    readonly safeToDrop: boolean;
}
/** The result of a residency audit. */
export interface NexusResidencyScanResult {
    /** Absolute path of the project store. */
    readonly projectStorePath: string;
    /** Absolute path of the global store. */
    readonly globalStorePath: string;
    /** `false` when either store is missing; findings are then empty. */
    readonly bothStoresExist: boolean;
    /** Tables resident where they should not be. */
    readonly findings: readonly NexusResidencyFinding[];
    /** Findings whose removal is provably lossless. */
    readonly safeToDropCount: number;
    /**
     * Findings that are NOT safe to drop — a populated orphan, or a bare name
     * that resolves in two schemas. These need a decision, not a cleanup.
     */
    readonly needsDecisionCount: number;
}
/**
 * Audit where the nexus tables actually live, against where they must live.
 *
 * Read-only — opens both stores as snapshots and writes nothing.
 *
 * @param projectRoot - absolute path to the project root.
 * @param cleoHome - absolute path to the global cleo home.
 * @returns the audit; `findings` is empty when residency is correct.
 *
 * @task T12158
 */
export declare function scanNexusSchemaResidency(projectRoot: string, cleoHome: string): NexusResidencyScanResult;
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