fix: prevent runtime permission stalls and Agent reconnect failures

Execute could stall on workspace-external access or native child-session
permissions, while structured questions could be lost or answered incorrectly.
Route owned OpenCode descendant interactions, correct Continue question and
custom-answer handling, and resolve DSH Execute ACP permissions without a
second approval. Ask remains read-only and unrelated sessions stay isolated.

Restore the required DSH session projection service. Reuse offline OpenCode
configuration by plugin version, remove unused npm shims from remote payloads,
normalize dependency modes, and accept real compound descriptors up to 4 MiB.
Fix intermittent Agent attach rejection and closed-handshake waits.

Add focused and real-Runtime regressions, document interaction boundaries and
validation evidence, and include the existing application/tool navigation
design drafts. Those navigation changes are design-only, not implemented UI.

Validation: full suite 3597 passed, 0 failed, 61 skipped across 338 files;
typecheck, lint, release-note verification, whitespace and relative-link checks
passed. Current-source Linux x64 installation, Ask/Execute, native subagent
external writes, reconnect and stop/bootstrap passed with 10 completed real
model calls, 13 native endpoint tests and 20 consecutive handshakes.
System sleep/wake and release CI packaging remain unverified.

Release note: 修复 Execute 访问工作区外目录或运行原生子代理时卡在权限等待的问题，并恢复 OpenCode 与 Continue 结构化问答的正确转交。修复远程 Agent 安装与重连失败；Ask 仍保持只读，任意终端密码或业务确认不会自动代答。

src/agent-daemon/private-endpoint.ts

@@ -51,7 +51,8 @@ const challengeResponsePacketSchema = z
     controllerId: agentIdentifierSchema,
     clientNonce: agentIdentifierSchema,
     protocol: protocolVersionSchema,
-    response: agentIdentifierSchema
+    // A SHA-256 HMAC is canonical Base64URL, not an application identifier.
+    response: z.string().regex(/^[A-Za-z0-9_-]{42}[AEIMQUYcgkosw048]$/u)
   })
   .strict()
 
@@ -400,7 +401,7 @@ export async function probeAuthenticatedEndpoint(options: {
     const challenge = challengePacketSchema.parse(await readPacket(socket))
     const verifier = new InstallationChallengeVerifier(options.secret)
     const controllerId = 'lifecycle-health'
-    const clientNonce = randomBytes(24).toString('base64url')
+    const clientNonce = `health-${randomBytes(24).toString('base64url')}`
     await writePacket(socket, {
       type: 'response',
       version: 1,
@@ -559,6 +560,9 @@ async function readExactly(socket: Socket, byteLength: number): Promise<Buffer>
       remaining -= chunk.byteLength
       continue
     }
+    if (socket.destroyed || socket.readableEnded) {
+      throw new Error('Attach socket closed during handshake')
+    }
     await new Promise<void>((resolve, reject) => {
       const onReadable = (): void => {
         cleanup()
@@ -575,10 +579,12 @@ async function readExactly(socket: Socket, byteLength: number): Promise<Buffer>
       const cleanup = (): void => {
         socket.off('readable', onReadable)
         socket.off('end', onEnd)
+        socket.off('close', onEnd)
         socket.off('error', onError)
       }
       socket.once('readable', onReadable)
       socket.once('end', onEnd)
+      socket.once('close', onEnd)
       socket.once('error', onError)
     })
   }
@@ -588,6 +594,8 @@ async function readExactly(socket: Socket, byteLength: number): Promise<Buffer>
 async function readExactlyFromStream(
   stream: NodeJS.ReadableStream & {
     read(size?: number): Buffer | null
+    destroyed?: boolean
+    readableEnded?: boolean
   },
   byteLength: number
 ): Promise<Buffer> {
@@ -601,6 +609,9 @@ async function readExactlyFromStream(
       remaining -= bytes.byteLength
       continue
     }
+    if (stream.destroyed || stream.readableEnded) {
+      throw new Error('Attach relay input closed during preface')
+    }
     await new Promise<void>((resolve, reject) => {
       const onReadable = (): void => {
         cleanup()
@@ -617,10 +628,12 @@ async function readExactlyFromStream(
       const cleanup = (): void => {
         stream.removeListener('readable', onReadable)
         stream.removeListener('end', onEnd)
+        stream.removeListener('close', onEnd)
         stream.removeListener('error', onError)
       }
       stream.once('readable', onReadable)
       stream.once('end', onEnd)
+      stream.once('close', onEnd)
       stream.once('error', onError)
     })
   }