[FEATURE]: Wire the permission.ask plugin hook

[jacobprall]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

The permission.ask hook is declared in the Hooks interface (@opencode-ai/plugin) but never triggered from the permission engine. Plugins that implement permission.ask are silently ignored.

Wiring it would let plugins auto-allow or auto-deny permission requests before prompting the user — useful for governance sidecars, policy engines, and MCP integrations that manage permissions externally.

Proposed behavior:

• Built-in ruleset evaluation stays unchanged (deny short-circuits, allow passes).
• When rules evaluate to "ask", fire Plugin.trigger("permission.ask", ...) after the request enters the pending queue.
• If the plugin sets status:"allow" → resolve immediately, no prompt.
• If the plugin sets status:"deny" → throw DeniedError, no prompt.
• If the plugin leaves status:"ask" or throws → normal prompt flow.

Small change (~40 lines in permission/index.ts), zero regressions on existing tests.

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• permission.ask plugin hook is defined but not triggered #7006: permission.ask plugin hook is defined but not triggered — describes the same root cause (hook declared in the SDK but never fired by the permission engine) and even includes a nearly identical proposed fix.

[jbro]

Filed #22311, exposing ask() on tool.execute.before so plugins can initiate permission requests from the pre-tool hook. Complementary to this issue. Have a branch ready if it's wanted?