/**
 * @fileoverview Migration v5 — skill_versions table
 * @module @skillsmith/core/db/migrations/v5-skill-versions
 * @see SMI-skill-version-tracking Wave 1
 *
 * Creates the skill_versions table for persistent content-hash-based
 * version tracking. Deliberately uses no FK constraint on skill_id so
 * that version history is preserved even when a skill is removed from
 * the registry (soft reference by design).
 *
 * No change_type column in this migration — deferred to Wave 2 per plan.
 */
/**
 * SQL for the skill_versions migration (v5).
 *
 * Table columns:
 *  - id           AUTOINCREMENT surrogate key
 *  - skill_id     Registry skill identifier (TEXT, not FK)
 *  - content_hash SHA-256 hex digest of skill content proxy
 *  - recorded_at  Unix epoch seconds (DEFAULT unixepoch())
 *  - semver       Optional semver string from skill metadata
 *  - metadata     Optional JSON blob for future extension
 *
 * Indexes:
 *  - UNIQUE (skill_id, content_hash) — makes recordVersion idempotent
 *    via INSERT OR IGNORE
 *  - (skill_id, recorded_at DESC) — efficient "latest version" queries
 */
export declare const MIGRATION_V5_SQL = "\nCREATE TABLE IF NOT EXISTS skill_versions (\n  id           INTEGER PRIMARY KEY AUTOINCREMENT,\n  skill_id     TEXT    NOT NULL,\n  content_hash TEXT    NOT NULL,\n  recorded_at  INTEGER NOT NULL DEFAULT (unixepoch()),\n  semver       TEXT,\n  metadata     TEXT\n);\n\nCREATE UNIQUE INDEX IF NOT EXISTS idx_skill_versions_skill_hash\n  ON skill_versions(skill_id, content_hash);\n\nCREATE INDEX IF NOT EXISTS idx_skill_versions_skill_recorded\n  ON skill_versions(skill_id, recorded_at DESC);\n";
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