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.

[tirth8205]

The fixes here are correct and important — hook format now matches Claude Code's actual schema (nested hooks array with type:command), PreCommit removed (invalid hook event), --repo path is properly shell-quoted via json.dumps(), and get_docs_section_tool repo_root param is restored for backwards compat.

However the tests have a platform-specific bug that will fail on Linux/macOS CI:

The three assertions like this:
assert hooks[0]['hooks'][0]['command'].endswith('--repo "E:/repo"')

Path('/repo').resolve().as_posix() returns '/repo' on Linux/macOS, not 'E:/repo' — the 'E:' prefix is your Windows drive. Please replace these three assertions with OS-agnostic checks, for example:

import json
from pathlib import Path
expected_arg = json.dumps(Path('/repo').resolve().as_posix())
assert f'--repo {expected_arg}' in command

Or simply check that the command contains '--repo' and that the path is quoted (contains a double-quote character) without hardcoding the drive letter.

Please fix the three affected test assertions and rebase on main, then this is good to merge.