Update Kimi CLI version detection to use GitHub releases

Changed Kimi version detection from custom pyproject.toml parsing to
using GitHub releases API, which is more standard and reliable.

Changes:
- Updated internal/registry/agents.json:
  - Changed package_manager from "uv" to "github"
  - Changed package_name from "kimi-cli" to "MoonshotAI/kimi-cli"
- Uses existing getGitHubLatestRelease() function
- Fetches version from https://api.github.com/repos/MoonshotAI/kimi-cli/releases/latest

Benefits:
- More reliable: Uses official GitHub releases
- Simpler: Reuses existing infrastructure
- Standard: Consistent with other GitHub-based agents

Tested with `agentpipe agents list --outdated`:
- Successfully detects Kimi v0.40 from GitHub releases
- Correctly compares with installed version

All quality checks passing:
- Tests: go test ./... ✅
- Linting: golangci-lint run ✅
- Build: go build ✅

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: kevinelliott

internal/registry/agents.json

@@ -197,8 +197,8 @@
       "command": "kimi",
       "description": "Kimi CLI by Moonshot AI",
       "docs": "https://github.com/MoonshotAI/kimi-cli",
-      "package_manager": "uv",
-      "package_name": "kimi-cli",
+      "package_manager": "github",
+      "package_name": "MoonshotAI/kimi-cli",
       "install": {
         "darwin": "uv tool install --python 3.13 kimi-cli",
         "linux": "uv tool install --python 3.13 kimi-cli",