Fix: normalize Windows path spellings before plan-file containment check

[houhou8]

Problem

On MSYS/MinGW/Cygwin, the same directory can have multiple textual representations, and the two sides of the plan-file containment check may come from sources that use different forms:

git rev-parse --show-toplevel        -> C:/Users/name/project
CLAUDE_PROJECT_DIR from Claude Code  -> C:\Users\name\project
bash cd ... && pwd                    -> /c/Users/name/project

setup-rlcr-loop.sh compares these paths as strings. When the project root and plan path use different representations, affected Windows Git Bash users hit a hard failure at loop start even though the plan file is inside the project:

Error: Plan file must be within project directory

The existing canonicalization does not solve this mismatch because MSYS realpath preserves whichever path representation it is given rather than folding drive-letter and MSYS forms together.

Fix

Add to_posix_path() to hooks/lib/project-root.sh.

The helper converts drive-letter and backslash paths to the MSYS/Cygwin POSIX form using cygpath -u, with a pure-Bash fallback for Windows shells where cygpath is unavailable.

Apply it consistently to:

• CLAUDE_PROJECT_DIR
• the output of git rev-parse --show-toplevel
• the resolved plan path

This ensures that every path involved in the containment comparison uses the same representation. Arbitrary drive letters are supported, and paths containing spaces are preserved.

The helper is a no-op outside Windows environments, so a valid POSIX filename containing a backslash is not rewritten.

Also restrict the python3 fallback in canonicalize_path() and canonicalize_path_prefix() to non-Windows shells. A native Windows Python interpreter can interpret an MSYS path such as /c/x as a different drive-relative path:

/c/x -> C:\c\x

This silently produces an incorrect path. MSYS environments provide realpath, so disabling this fallback on Windows does not remove required functionality.

Testing

Add tests/test-path-normalization.sh covering:

• drive-letter and MSYS representations of the same directory
• backslash paths
• arbitrary drive letters
• project paths containing spaces
• non-Windows no-op behavior
• rejection of a plan genuinely outside the project
• rejection of prefix-sibling paths such as project-evil

End-to-end verification confirms that the fixed branch starts the RLCR loop successfully without manually exporting CLAUDE_PROJECT_DIR, while the current main branch fails with the incorrect containment error.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Normalize remaining realpath comparisons too

On MSYS/MinGW this switches PROJECT_ROOT to /c/..., but the methodology-analysis read guard still compares raw realpath "$FILE_PATH" against raw realpath "$PROJECT_ROOT"/$PROJECT_ROOT in hooks/loop-read-validator.sh lines 91 and 154-158. When Claude supplies a drive-letter path such as C:/repo/src/x during methodology analysis, MSYS realpath preserves that spelling while PROJECT_ROOT is now /c/repo, so neither prefix check matches and project files are allowed to be read despite that phase's project-read block. Please run those remaining realpath outputs through the same normalization before comparing.

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