fix(db): 外部驱动增加最低版本门，OceanBase 低于 0.1.12 时引导用户更新

[feigeCode]

Closes #249

Description

The host only checked whether an external database driver was installed, never which version. OceanBase drivers before 0.1.12 encoded u64 cells as decimal text, while the host struct field is u64, so reading a table with unsigned columns failed with invalid external driver response: invalid type: string "4", expected u64. The driver contract is already fixed on the driver side (navop-extensions#9, shipped as oceanbase 0.1.12), but installed drivers are never updated automatically and the host showed no hint, so users on 0.1.10/0.1.11 kept hitting an error they cannot act on.

This PR makes the host version-aware for external drivers:

• DriverRequirement::Required now carries minimum_version: Option<String>.
• required_external_driver declares a minimum version per driver id (currently oceanbase -> 0.1.12); undeclared drivers keep the old no-minimum behavior.
• The connection guard now uses driver_version_meets_minimum instead of a plain "is installed" check, so an installed-but-too-old driver also goes through the install/update flow, with the existing prompt text （最低版本 0.1.12）.
• The install flow reuses find_database_driver_entry_for_requirement, which refuses a marketplace entry below the required version.

Serialization and the driver contract are unchanged; this only decides whether a connection is opened or the user is asked to update the driver first.

Screenshot

Before	After
OceanBase connection with driver < 0.1.12 opens, then table read fails with a type error	Prompt 需要安装或更新驱动 …（最低版本 0.1.12）, one click installs/updates from the marketplace

How to Test

1. cargo test -p extension-runtime — 215 passed, 1 pre-existing failure (extension_runtime_wasm_contract_tests::db_tree_action_runs_registered_wasm_component), which also fails on a clean main checkout without this change.
2. New test oceanbase_external_driver_requires_a_minimum_version asserts required_driver_for_config returns minimum_version: Some("0.1.12") for oceanbase, and that driver_version_meets_minimum rejects 0.1.11 while accepting 0.1.12 / 0.1.13.
3. Existing tests updated for the new field: duckdb_requires_duckdb_marketplace_driver, external_database_requires_its_driver_id (both minimum_version: None).
4. cargo clippy -p extension-runtime --all-targets — no warnings in the touched files.

Checklist

• I have read the CONTRIBUTING document and followed the guidelines.
• Reviewed the changes in this PR and confirmed AI generated code (If any) is accurate.
• Passed cargo run for story tests related to the changes.
• Tested macOS, Windows and Linux platforms performance (if the change is platform-specific)