♻️ refactor: remove chat-plugin-sdk (#13512)

* ♻️ refactor: remove @lobehub/chat-plugin-sdk dependency

Plugins have been deprecated. This removes the SDK entirely:

- Define built-in ToolManifest, ToolManifestSettings, ToolErrorType types
- Delete src/features/PluginsUI/ (plugin iframe rendering)
- Delete src/store/tool/slices/oldStore/ (deprecated plugin store)
- Delete src/server/services/pluginGateway/ (plugin gateway)
- Delete src/app/(backend)/webapi/plugin/gateway/ (plugin API route)
- Migrate all ~50 files from SDK imports to @lobechat/types
- Remove @lobehub/chat-plugin-sdk, @lobehub/chat-plugins-gateway deps
- Remove @swagger-api/apidom-reference override and patch

Fixes LOBE-6655

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* 🐛 fix: add missing getInstalledPlugins mock in customPlugin test

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* 🔧 chore: increase Vercel build memory limit to 8192MB

The 6144MB limit was causing OOM during Vite SPA chunk rendering.
Aligned with other build commands that already use 8192MB.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* ♻️ refactor: unify default tool type to builtin and fix CustomRender

- Remove `invokeDefaultTypePlugin` — default type now falls through to builtin in both server and client execution paths
- Fix `CustomRender` to actually render builtin tool components via `getBuiltinRender` instead of always returning null
- Increase SPA build memory limit from 7168MB to 8192MB to fix OOM

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* ♻️ refactor: remove legacy plugin gateway and type-specific invocations

- Delete `runPluginApi`, `internal_callPluginApi`, `invokeMarkdownTypePlugin`, `invokeStandaloneTypePlugin`
- Remove plugin gateway endpoint (`/webapi/plugin/gateway`) from URL config
- Remove special `builtin → default` runtimeType mapping in plugin model
- Clean up unused imports and related tests

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* 🐛 fix: add 'builtin' to runtimeType union to fix type error

Use ToolManifestType instead of inline union for runtimeType fields
so that 'builtin' is included as a valid type.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pnpm-workspace.yaml

@@ -9,8 +9,6 @@ onlyBuiltDependencies:
   - '@lobehub/editor'
 
 overrides:
-  '@lobehub/chat-plugin-sdk>swagger-client': 3.36.0
-  '@swagger-api/apidom-reference': 1.1.0
   jose: ^6.1.3
   stylelint-config-clean-order: 7.0.0
   pdfjs-dist: 5.4.530
@@ -18,5 +16,4 @@ overrides:
   react-dom: 19.2.4
 
 patchedDependencies:
-  '@swagger-api/apidom-reference': patches/@swagger-api__apidom-reference.patch
   '@upstash/qstash': patches/@upstash__qstash.patch