`src/hooks/executor.rs` — `HookExecutor`

Runs the hooks: pre-checks with short-circuit semantics, notifications with none.

Key items

• HookExecutor::new() (Headless) / with_interactivity(...) / with_hook(...) / register(...); hook_count().
• check_pre_tool_use(ctx) -> HookAction — first non-Allow wins; apply_interactivity downgrades Ask in Headless with the message preserved in the reason.
• check_pre_compact(ctx) -> CompactResult — abort-first; instructions accumulate into the context as hooks run; last new_instructions wins; additional_context extends.
• Notify methods (all hooks run): notify_post_tool_use, notify_post_compact, notify_run_start/end (+ *_async ready-future wrappers — no task spawning).

Behavior notes

• Hooks are stored in registration order, append-only, never reordered; the same instance registered twice runs twice.
• Empty executor → Allow / default CompactResult in both interactivity modes.
• The engine consults this at the exact boundaries: pre-tool before dispatch (block → soft error result), pre-compact before a pass.

Deep dive: Hooks.