[BUG] namespace_plugin_rel resultMap maps wrong column to wrong property (enabled never populated)

- severity: High
- files: `shenyu-admin/src/main/resources/mappers/namespace-plugin-rel-sqlmap.xml:29`
- description: `BaseResultMap` line 29 is ``. Two errors: (a) the real column is `enabled` (per `Base_Column_List:38` and `schema.sql:1428`), not `enable`; (b) it maps to property `sort` instead of `enabled`. The `enabled` property of `NamespacePluginRelDO` has no mapping at all. `listByNamespaceId` (line 381, `resultMap="BaseResultMap"`) is the consumer.
- impact: Callers of `namespacePluginRelMapper.listByNamespaceId` observe null `enabled` and corrupted `sort`; downstream plugin-enable-state logic is silently wrong.
- suggested_fix: Replace line 29 with ``.
- confidence: High
- related_existing: none. Pure mapper/XML defect not in baseline.

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_Identified during the 2026-08-02 deep re-scan; full list in [`docs/scan2-2026-08-02/00-consolidated-critical-high.md`](docs/scan2-2026-08-02/00-consolidated-critical-high.md)._

Inspect shenyu-admin/src/main/resources/mappers/namespace-plugin-rel-sqlmap.xml at line 29, then compare Base_Column_List, schema.sql:1428, and NamespacePluginRelDO. Trace listByNamespaceId at line 381 using BaseResultMap. Done means the enabled column populates enabled and sort is no longer overwritten by that mapping.

Written by the indexing model from the issue text.