feat: add CodeBuddy CN preset and hook installer (rebased on new framework)

[Krishnachaitanyakc]

Summary

Adds support for CodeBuddy CN (Tencent's Claude Code-compatible IDE plugin) as requested in #1035, rebased on the new agent presets architecture.

This is a fresh PR replacing #1112 (closed pre-rewrite).

What's added

• presets/codebuddy.rs — pure parser implementing AgentPreset. Extracts events from CodeBuddy CN's Claude-shaped hook payloads (PreToolUse/PostToolUse, tool_name, tool_input).
• mdm/agents/codebuddy.rs — CodeBuddyInstaller for settings.json hooks. Cross-platform (macOS / Linux / Windows). Mirrors ClaudeCodeInstaller's migration, idempotency, and dedup logic.
• Claude preset guard — is_codebuddy_hook_payload rejects payloads with client: "CodeBuddyIDE" or transcript paths under CodeBuddyExtension, preventing misrouting.
• AI_AUTHOR_NAMES — "codebuddy" added so git-ai blame attributes CodeBuddy commits as AI.

Key differences from Claude Code

	Claude Code	CodeBuddy CN
tool_input filepath field	file_path (snake_case)	filePath (camelCase)
cwd	Real project dir	Always "/" (known CodeBuddy bug)
Transcript layout	Single JSONL file	index.json + messages/{id}.json directory
Catch-all matcher	"*"	".*" (CodeBuddy requires regex)
Identifier	(none in payload)	client: "CodeBuddyIDE", model: "glm-5.0-turbo"

The cwd: "/" workaround leverages the new orchestrator's design: repo discovery for PreFileEdit/PostFileEdit events uses file_paths[0] (worktree_root_for_path), not cwd. So as long as tool_input.filePath is the absolute path to a file in a git repo, attribution works.

Deferred (not in this PR)

The CodeBuddy CN transcript format (index.json + messages/{id}.json with double-encoded JSON in the message field) needs a dedicated reader. For v1 this PR sets transcript_source to point at index.json with ClaudeJsonl format as a placeholder — the existing reader simply finds no events. Hook-based AI attribution works without it. Fixtures in tests/fixtures/codebuddy-session/ document the layout. A follow-up commit can add the dedicated reader if desired.

Files changed

New:

• src/commands/checkpoint_agent/presets/codebuddy.rs (~280 lines including 12 unit tests)
• src/mdm/agents/codebuddy.rs (~640 lines including 16 unit tests covering install/uninstall/check scenarios)
• tests/integration/codebuddy.rs (~210 lines, 6 tests: 3 in-process routing + 3 E2E with TestRepo)
• tests/fixtures/codebuddy-session/index.json + messages/msg00{1,2,3}.json

Modified:

• src/commands/checkpoint_agent/presets/claude.rs — added is_codebuddy_hook_payload guard + 2 tests
• src/commands/checkpoint_agent/presets/mod.rs — registered preset
• src/mdm/agents/mod.rs — registered installer
• tests/integration/main.rs — registered test module
• tests/integration/repos/test_file.rs — added "codebuddy" to AI_AUTHOR_NAMES
• tests/integration/repos/test_repo.rs — added "codebuddy" to is_known_checkpoint_preset so the test harness routes args correctly

Test plan

• cargo fmt --check passes
• cargo clippy --all-targets -- -D warnings passes
• RUSTDOCFLAGS="-D warnings" cargo doc --no-deps passes
• All 1460 lib unit tests pass (cargo test --lib)
• cargo test --test integration -- codebuddy — all 6 pass
• cargo test --test integration -- claude_code::test — all 18 pass (verifies the new Claude guard didn't regress)
• cargo test --test integration -- windsurf:: — all 16 pass (verifies the test harness change didn't regress)
• No println!/dbg! in production code
• Standalone E2E: piped a sample CodeBuddy CN PreToolUse and PostToolUse hook payload through git-ai checkpoint codebuddy --hook-input stdin against a temp git repo; verified the codebuddy preset accepts and the claude preset rejects (with guidance message).

Closes #1035

---

[svarlamov]

Thank you for the PR @Krishnachaitanyakc! Btw you can ignore that Windows test failure -- unrelated and fixed on main.

[xenv]

CodeBuddy also has another product line: CodeBuddy Code (CLI) at https://www.codebuddy.ai/cli. It shares the same configuration file as CodeBuddy IDE (meaning that install hooks will also affect CodeBuddy CLI), but its hook requests differ somewhat from those of the IDE, especially regarding things like conversation history. I think it’s necessary to consider compatibility for the CLI scenario.