feat(coder): add hashline editing core + wire audit hooks into dispatch pipeline

Hashline editing: content-hash anchors for edit_file stale-patch detection.
Pure-JS xxHash32, line hash computation, validation with HashlineMismatchError,
256-entry hash dictionary. 6 files in apps/coder/src/services/hashline/.

Audit hooks: emitHook('tool.execute.after') wired in frame-emitter.ts for
completed/failed tool results. emitHook('turn.end') wired at terminal points
in dispatcher.ts (all 5 run functions: native, external, opencode, warm ACP,
claude SDK). Fire-and-forget, non-blocking.

apps/coder/src/services/frame-emitter.ts

@@ -19,9 +19,10 @@
 import type { Broker } from '@boocode/server/broker';
 import type { WsFrame } from '@boocode/contracts/ws-frames';
 import type { AgentEvent } from './agent-backend.js';
-import { type AcpToolSnapshot, snapshotToWireToolCall } from './acp-tool-snapshot.js';
+import { type AcpToolSnapshot, snapshotToWireToolCall, mapToolLifecycleStatus } from './acp-tool-snapshot.js';
 import { mergeTaskCommands, getTaskCommands } from './agent-commands-cache.js';
 import type { DcpStreamStripper } from './dcp-strip.js';
+import { emitHook } from '../plugins/host.js';
 
 export interface FrameEmitterOpts {
   broker?: Broker;
@@ -91,8 +92,29 @@ export function makeFrameEmitter(opts: FrameEmitterOpts): FrameEmitter {
         }
         break;
       case 'tool_call':
+        toolSnapshots.set(e.toolCall.toolCallId, e.toolCall);
+        if (canStream()) {
+          broker!.publishFrame(sessionId!, {
+            type: 'tool_call',
+            message_id: assistantId!,
+            chat_id: chatId!,
+            tool_call: snapshotToWireToolCall(e.toolCall),
+          } as WsFrame);
+        }
+        break;
       case 'tool_update':
         toolSnapshots.set(e.toolCall.toolCallId, e.toolCall);
+        {
+          const lifecycle = mapToolLifecycleStatus(e.toolCall.status, e.toolCall.rawOutput);
+          if (lifecycle === 'completed' || lifecycle === 'failed') {
+            void emitHook('tool.execute.after', {
+              toolName: e.toolCall.title,
+              args: e.toolCall.rawInput,
+              result: e.toolCall.rawOutput,
+              duration: undefined,
+            });
+          }
+        }
         if (canStream()) {
           broker!.publishFrame(sessionId!, {
             type: 'tool_call',