fix: restore packaged runtimes and ship macOS DMG only

Desktop 0.12.7 omitted OpenCode's offline node_modules because the resource
copier excludes node_modules at its source root. Copy from the parent and
verify every prepared configuration file in the final package. Bundle DSH
session projection with the unpacked Host instead of leaving an ASAR-only
external import, and reject external DeepSeek imports in shipped chunks.

Run packaged OpenCode plugin import and the real DSH UtilityProcess handshake
in Windows x64 CI before removing unpacked output. Add regressions using the
actual electron-builder copier and Vite externalization configuration.

Prepare approved Desktop 0.12.8 notes and change macOS defaults and CI to DMG
only. Update aggregation, website downloads and update readers for 12
installers and 20 assets. Current readers retain historical DMG/ZIP support;
the user accepts that older macOS GitHub readers and all older mirror readers
need manual upgrades. Agent remains 0.11.21, with no new Agent or LoongArch tag.

Validation: 3608 tests passed, 0 failed, 61 skipped across 339 files;
typecheck, lint, release-note validation, website static checks and 18 website
tests passed. No local production build or packaged-app launch was performed
at the user's request; actual packaged startup validation runs in CI.

Release note: 修复安装后 OpenCode 离线依赖缺失和 DeepSeek Harness Host 启动退出；macOS 改为仅提供 DMG，受影响旧版用户需从下载页手动升级。

resources/release-notes.json

@@ -1,6 +1,38 @@
 {
   "formatVersion": 1,
   "releases": [
+    {
+      "version": "0.12.8",
+      "releasedAt": "2026-09-08",
+      "notes": {
+        "zh-CN": {
+          "highlights": [],
+          "features": [],
+          "fixes": [
+            "**修复 OpenCode 启动失败。** 安装包补齐离线配置依赖，避免因缺少 `@opencode-ai/plugin/package.json` 无法启动。升级后无需手动安装 Node.js 或 npm 依赖。",
+            "**修复 DeepSeek Harness Host 启动退出。** 将必需的会话组件完整打入 Host，避免安装后提示“Host 启动前退出（code 1）”。现有模型配置保持不变。",
+            "**macOS 仅提供 DMG。** Intel 与 Apple 芯片版本不再构建或发布 ZIP。Windows 和 Linux 的安装包格式保持不变。"
+          ],
+          "notices": [
+            "旧版 macOS 的 GitHub 更新检查，以及所有平台的旧版镜像更新检查可能无法识别新清单，请从官方下载页手动升级至 `0.12.8`。",
+            "Agent 继续使用 `0.11.21`，本次不重发 Agent，也不构建 LoongArch 实验预览。"
+          ]
+        },
+        "en-US": {
+          "highlights": [],
+          "features": [],
+          "fixes": [
+            "**Fixed OpenCode startup failures.** Desktop packages now include the offline configuration dependencies, avoiding startup failures caused by a missing `@opencode-ai/plugin/package.json`. No manual Node.js or npm dependency installation is needed after upgrading.",
+            "**Fixed DeepSeek Harness Host startup exits.** Required session components are bundled into the Host, preventing the “Host exited before startup (code 1)” error after installation. Existing model settings remain unchanged.",
+            "**DMG-only macOS releases.** Intel and Apple silicon versions no longer build or publish ZIP packages. Windows and Linux package formats are unchanged."
+          ],
+          "notices": [
+            "Older macOS GitHub update checks and older mirror update checks on all platforms may reject the new manifest. Upgrade manually to `0.12.8` from the official download page.",
+            "Agent remains at `0.11.21`; this release does not republish the Agent or include a LoongArch preview."
+          ]
+        }
+      }
+    },
     {
       "version": "0.12.7",
       "releasedAt": "2026-09-08",