Fix hook repo quoting and restore docs repo_root

[GrimoireScribe]

Summary

Following feedback on #154, this separates the remaining non-JSX fixes into their own PR.

This PR does two things:

• quotes generated Claude hook --repo paths so repos under paths with spaces do not break
• restores the repo_root parameter on get_docs_section_tool so the MCP schema remains backward-compatible

Why

The JSX parser work now lives on its own branch/PR.
These two changes are still useful independently:

• generated hook commands should be shell-safe for repo paths with spaces
• existing callers that pass repo_root to get_docs_section_tool should not break

Verification

Ran targeted validation locally for the affected areas.