ADR-0090 D3 leftovers in plugin-sharing: sys_record_share `role` recipient enum + "角色及下级" translations

[os-zhuang]

What

Two D3 (word-ban / rename) leftovers in `packages/plugins/plugin-sharing`:

1. `src/objects/sys-record-share.object.ts` (~L138): the `recipient_type` enum is still `['user', 'group', 'role', 'unit_and_subordinates', 'guest']` — the sharing recipient rename (`role` → `position`, ADR-0090 D3) reached `sys_sharing_rule` but not the share-grant table. Stored rows may carry the old value, so this needs a data migration pass, not just an enum edit.
2. Generated translations still label `unit_and_subordinates` as "角色及下级" (zh-CN) / "ロールと下位階層" (ja-JP) — "role" vocabulary in UI copy, which D3 bans. Source label fix + `i18n-extract` regeneration.

Fix

• Migrate `sys_record_share.recipient_type` `'role'` → `'position'` (enum + stamped rows) in the same style as the D1/D4 grandfathering pass.
• Update the field labels/descriptions and regenerate the plugin's translation bundles ("业务单元及下级" /「ビジネスユニットと下位階層」).

Found while aligning docs + showcase to ADR-0090 (P4 follow-up).

[os-zhuang]

Fixed in #2745 (merged): see the PR body for the root cause and verification (fresh-boot browser dogfood + full suite green).