feat: add CodeBuddy support

[studyzy]

Summary

This PR adds native support for CodeBuddy as a supported CLI client, alongside existing support for Claude Code and Codex.

CodeBuddy is a CLI coding agent that shares a similar architecture with Claude Code — it supports MCP server configuration, hooks (PostToolUse, Notification, SessionStart, Stop), and the same tool naming conventions (read, grep, edit, etc.).

Changes

New features

• Client setup handler (ClientSetupHandlerCodeBuddy): Enables serena setup codebuddy to auto-configure the MCP server. Includes version detection and stderr suppression.
• CodeBuddy context (contexts/codebuddy.yml): A single-project context that disables overlapping tools (read_file, search_for_pattern, execute_shell_command, etc.) and encourages the agent to prefer Serena's symbolic tools.
• Hook support: Extends the existing hook system (serena-hooks) to recognize --client=codebuddy, applying the same remind, activate, cleanup, and auto-approve hooks as Claude Code.

Documentation

• README.md — added CodeBuddy alongside Claude Code and Codex in client lists.
• docs/02-usage/030_clients.md — new "CodeBuddy" section with setup instructions (both auto and manual), MCP configuration examples, hook configuration JSON, and hook descriptions.
• docs/02-usage/020_running.md, docs/02-usage/040_workflow.md, docs/02-usage/050_configuration.md — updated references to include CodeBuddy in lists of single-project contexts and supported clients.
• CHANGELOG.md — updated a reference to include CodeBuddy in a prior fix note.

Bug fixes

• Suppress stderr noise in is_applicable() checks: execute_shell_command() calls in ClaudeCode and Codex handlers now use capture_stderr=True, preventing shell "command not found" errors from leaking to the terminal when a client binary is not installed.
• Relaxed version check for CodeBuddy: CodeBuddy's --version outputs only a version number (e.g. "2.106.4") without a recognizable binary name, so the version check only validates the return code rather than parsing stdout content.

Files changed

CHANGELOG.md                                       |   2 +-
README.md                                          |   6 +-
docs/02-usage/020_running.md                       |   6 +-
docs/02-usage/030_clients.md                       |  93 +++++++++++++-
docs/02-usage/040_workflow.md                      |   4 +-
docs/02-usage/050_configuration.md                 |   3 +-
src/serena/config/client_setup.py                  |  27 ++++-
src/serena/hooks.py                                |   5 +-
src/serena/resources/config/contexts/codebuddy.yml |  52 ++++++++
10 files changed, 183 insertions(+), 21 deletions(-)

Testing

• Verified serena setup codebuddy correctly detects and configures CodeBuddy.
• Verified hooks (remind, activate, cleanup, auto-approve) function correctly with --client=codebuddy.
• Verified the CodeBuddy context properly disables overlapping tools and enforces single-project mode.