fix: update bundled DeepSeek Harness to rc.8

The desktop runtime still pinned the rc.6 Harness family. It now uses the coherent rc.8 package set, adapts the revised image-attachment limits and error contract, and derives release checks from the lockfile. The managed SSH Agent package remains unchanged.

Release note: 内置 DeepSeek Harness 已升级至 0.1.0-rc.8，并适配新版图片附件限制；托管 SSH Agent 包不受影响。

src/main/agent/goodbuddy-harness-control-plane.test.ts

@@ -22,7 +22,7 @@ function controlPlane() {
       provider: 'goodbuddy',
       model: 'deepseek-test',
       workspace: resolve('workspace'),
-      harnessVersion: '0.1.0-rc.6',
+      harnessVersion: '0.1.0-rc.8',
       execution: { mode: 'host' },
       credentialRefs: ['GOODBUDDY_API_KEY'],
       skills: []
@@ -75,7 +75,7 @@ function stubAgentContext() {
     provider: 'goodbuddy',
     model: 'deepseek-test',
     workspace: resolve('workspace'),
-    harnessVersion: '0.1.0-rc.6',
+    harnessVersion: '0.1.0-rc.8',
     execution: { mode: 'host' },
     credentialRefs: ['GOODBUDDY_API_KEY'],
     skills: [],
@@ -172,7 +172,7 @@ describe('GoodBuddy Harness internal control plane', () => {
       model: 'vision-test',
       supportsImageInput: true,
       workspace: resolve('workspace'),
-      harnessVersion: '0.1.0-rc.6',
+      harnessVersion: '0.1.0-rc.8',
       execution: { mode: 'host' },
       credentialRefs: ['GOODBUDDY_API_KEY'],
       skills: []
@@ -223,7 +223,7 @@ describe('GoodBuddy Harness internal control plane', () => {
 
     subject.releaseAttachments(refs)
     await expect(store.readImage(refs[0]!)).rejects.toMatchObject({
-      code: 'NOT_FOUND'
+      code: 'ATTACHMENT_NOT_FOUND'
     })
     await expect(
       subject.storePromptImages([