docs: add LINE ACP support and plugin requireApproval hook docs

- LINE: document ACP conversation binding support (#45826)
- Plugins: document requireApproval in before_tool_call hook semantics (#55339)

docs/channels/line.md

@@ -184,6 +184,15 @@ The LINE plugin also ships a `/card` command for Flex message presets:
 /card info "Welcome" "Thanks for joining!"
 ```
 
+## ACP support
+
+LINE supports ACP (Agent Communication Protocol) conversation bindings:
+
+- `/acp spawn <agent> --bind here` binds the current LINE chat to an ACP session without creating a child thread.
+- Configured ACP bindings and active conversation-bound ACP sessions work on LINE like other conversation channels.
+
+See [ACP agents](/tools/acp-agents) for details.
+
 ## Outbound media
 
 The LINE plugin supports sending images, videos, and audio files through the agent message tool. Media is sent via the LINE-specific delivery path with appropriate preview and tracking handling:

docs/plugins/building-plugins.md

@@ -149,9 +149,12 @@ Hook guard semantics to keep in mind:
 
 - `before_tool_call`: `{ block: true }` is terminal and stops lower-priority handlers.
 - `before_tool_call`: `{ block: false }` is treated as no decision.
+- `before_tool_call`: `{ requireApproval: true }` pauses agent execution and prompts the user for approval via the exec approval overlay, Telegram buttons, Discord interactions, or the `/approve` command on any channel.
 - `message_sending`: `{ cancel: true }` is terminal and stops lower-priority handlers.
 - `message_sending`: `{ cancel: false }` is treated as no decision.
 
+The `/approve` command handles both exec and plugin approvals with automatic fallback. Plugin approval forwarding can be configured independently via `approvals.plugin` in config.
+
 See [SDK Overview hook decision semantics](/plugins/sdk-overview#hook-decision-semantics) for details.
 
 ## Registering agent tools