feat(backend): setup mcp, image upload, and skills

docs/testing/llm-unifier-helper-2-backend-testing.md

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+# LLM Unifier Helper-2 Backend Testing Report
+
+Date: 2026-04-06
+
+## Scope
+This report validates every backend functionality listed in:
+- `docs/backend/llm-unifier-helper-2.md`
+
+All test cases include inline comments that describe which helper-2 requirement they cover.
+
+## Test Files
+- `server/src/modules/llm/llm-unifier.providers.test.ts`
+- `server/src/modules/llm/llm-unifier.sessions.test.ts`
+- `server/src/modules/llm/llm-unifier.images.test.ts`
+- `server/src/modules/llm/llm-unifier.mcp.test.ts`
+- `server/src/modules/llm/llm-unifier.skills.test.ts`
+
+## package.json Scripts
+- `test:server` now includes the full unifier suite.
+- Added `test:server:llm-unifier-2` for running only helper-2 unifier coverage.
+
+## Commands Used
+```powershell
+npm run typecheck:server
+npm run test:server:llm-unifier-2
+npm run test:server
+```
+
+## Results
+- `typecheck:server`: pass
+- `test:server:llm-unifier-2`: pass (`30/30`)
+- `test:server`: pass (`30/30`)
+
+## Requirement Coverage Matrix
+| Helper-2 requirement | Test coverage |
+| --- | --- |
+| Universal image upload into `.cloudcli/assets` | `llmAssetsService stores uploaded images in .cloudcli/assets` |
+| Image upload validation for supported image mime types | `llmAssetsService rejects unsupported image mime types` |
+| Claude image prompt as content blocks with base64 images | `claude provider builds async prompt payload with base64 image blocks` |
+| Codex image prompt via `local_image` entries | `codex provider sends local_image prompt items when image paths are provided` |
+| Gemini/Cursor image handling by appending image path array to prompt | `gemini and cursor providers append image path arrays to prompts` |
+| Start payload imagePaths validation | `llmService rejects invalid imagePaths payloads before provider execution` |
+| MCP list grouped by User/Local/Project | `llmMcpService handles claude MCP scopes/transports with file-backed persistence` |
+| MCP add/remove/update behavior backed by provider config files | `llmMcpService handles claude MCP scopes/transports with file-backed persistence`, `llmMcpService handles codex MCP TOML config and capability validation`, `llmMcpService handles gemini and cursor MCP JSON config formats` |
+| Claude MCP transports: stdio/http/sse and scopes: user/local/project | `llmMcpService handles claude MCP scopes/transports with file-backed persistence` |
+| Codex MCP transports: stdio/http and scopes: user/project | `llmMcpService handles codex MCP TOML config and capability validation` |
+| Gemini MCP transports: stdio/http/sse and scopes: user/project | `llmMcpService handles gemini and cursor MCP JSON config formats` |
+| Cursor MCP transports: stdio/http/sse and scopes: user/project | `llmMcpService handles gemini and cursor MCP JSON config formats` |
+| Global MCP adder supports only `http` and `stdio` and applies to all providers | `llmMcpService global adder writes to all providers and rejects unsupported transports` |
+| MCP run/connectivity checks (stdio and http) | `llmMcpService runProviderServer probes stdio and http MCP servers` |
+| Claude skills fetch (user/project/plugin) and plugin namespacing | `llmSkillsService lists claude user/project/plugin skills with proper invocation names` |
+| Codex skills fetch (repo/user/admin/system path model; tested repo/user/system paths) and `$` invocation | `llmSkillsService lists codex skills from repo/user/system locations with dollar invocation` |
+| Gemini skills fetch from documented directories and `/` invocation | `llmSkillsService lists gemini skills from documented directories` |
+| Cursor skills fetch from documented directories and `/` invocation | `llmSkillsService lists cursor skills from documented directories` |
+| Existing unifier provider/session baseline behaviors remain passing | `llm-unifier.providers.test.ts`, `llm-unifier.sessions.test.ts` full suite |
+