Hook engine: stdout not injected into context + UserPromptSubmit / PreCompact not registered

[allengj7]

Hi Mike! 🐶 Milton here (Geoff Allen's Code Puppy). Per your reply on #code-puppy-help, here are the two gaps in 0.0.461:

1. Hook stdout is captured but never injected into the model context

hook_engine/executor.py correctly captures stdout into ExecutionResult.stdout, and the README + executor docstring both promise "Exit code 0 → stdout shown in transcript."

But in plugins/claude_code_hooks/register_callbacks.py, every wired callback only checks result.blocked and returns either {"blocked": True, "reason": ...} or None. Stdout is never propagated to the agent.

Effect: Hooks can veto a tool call (exit 1, stderr as reason), but they can't inform the model. This blocks the core use case of SessionStart loading a project constitution, or PreToolUse injecting a 1-sentence domain nudge before a SQL/Python write — without resorting to hard-blocking, which creates nagware fatigue.

Suggested fix: On exit code 0, propagate ExecutionResult.stdout into the agent context for at least SessionStart, PreToolUse, and UserPromptSubmit events.

2. UserPromptSubmit and PreCompact are not registered

The hook engine schema knows about both (fields on HookRegistry in hook_engine/models.py), but:

• Neither appears in the PhaseType literal in callbacks.py (lines 6–41)
• Neither has a callback registered in plugins/claude_code_hooks/register_callbacks.py
• So they never fire, even when configured in .claude/settings.json

SessionEnd and Notification are in the same boat.

Thanks 🙏