fix(mcp): use CodeBuddy project configuration path

[FenjuFu]

Summary

CodeBuddy Code reads project MCP configuration from the project root's .mcp.json, while TeamAI's default points at .codebuddy/mcp.json. Correct the default project path and document migration for teams with an explicit old path. User-scope targets, WorkBuddy and explicit team overrides retain their existing behavior.

The path is verified against the official CodeBuddy MCP documentation. It lists .mcp.json, then root mcp.json, for PROJECT scope; the tool subdirectory is not a project fallback.

Type of Change

• Bug fix
• Documentation update

Test Plan

• Upstream CI passed on contribution head b4150c74435e1c28288d3938db23f771f55d8164: Node 20/22 on Ubuntu/macOS, including type checks and the full unit suite with coverage.
• Fork CI passed the same four matrices.
• Build and the existing OpenCode recall E2E passed in both runs.
• Regression coverage checks the real default project path and the HTTP local agent's MCP installation destination. Updated the two existing assertions that still expected the old project path, including a check that the old project file is not created.
• Built CLI E2E: mcp list, mcp inject, repeated injection and mcp remove; verifies the root configuration, personal-server preservation, idempotency and unchanged user-scope data.
• Local type check, build and git diff --check passed.

The fork validation commit 7d8cbf3dd2cd30c3256af49225d1388202b81e30 directly follows the contribution head. Its only additional change is the existing CI push branch filter; source, tests, jobs, permissions and release workflow are unchanged by that validation commit.

The separate GitHub-provider full-surface E2E job was skipped in both runs; it is not included in the passing E2E coverage above. The fork has no configured fixture repository variable. The built-CLI scenario validates configuration delivery without calling a real MCP service or paid model API. Tencent CodeCC also passed on the current contribution head.

Related Issues

Fixes #474

Notes for Reviewers

Existing explicit toolPaths.codebuddy.mcpProject values are respected. The bilingual guides explain removal/reinjection when changing the old value; this patch does not move or delete existing configuration files. Claude Code and CodeBuddy share the root .mcp.json by their own configuration conventions.