feat(install): rename old manual binaries to .bak after Homebrew install

[AnnatarHe]

When migrating from manual install to Homebrew, rename existing ~/.shelltime/bin/shelltime and shelltime-daemon with .bak suffix so the shell resolves to the Homebrew-managed version instead.

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[claude]

PR Review: feat(install): rename old manual binaries to .bak after Homebrew install

Overall, this is a well-targeted fix for a real migration problem. The approach is straightforward and the implementation is mostly solid. A few items worth considering.

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No error handling on mv

If mv fails (e.g., permission error, read-only filesystem, disk full), the script silently continues and a subsequent shell session would still resolve to the old manual binary. Consider checking the exit code:

if [ -f "$HOME/.shelltime/bin/shelltime" ]; then
    if mv "$HOME/.shelltime/bin/shelltime" "$HOME/.shelltime/bin/shelltime.bak"; then
        echo "Renamed shelltime to shelltime.bak (now using Homebrew version)"
    else
        echo "Warning: Failed to rename shelltime -- old binary may shadow the Homebrew version"
    fi
fi

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Idempotency

Re-running after a successful Homebrew install is safe — the [ -f ... ] check prevents double-renaming. However, if a prior shelltime.bak already exists from an earlier run, mv will silently overwrite it. This is unlikely to matter in practice but worth being aware of.

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User clarity

The .bak files in ~/.shelltime/bin/ will persist indefinitely. Users may find them confusing and wonder if they are safe to delete. Consider noting them in the completion output or adding a cleanup step on subsequent install runs.

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Observation: shelltime-daemon consistency

Worth noting for context: the manual install path (lines 145–150) already installs the daemon binary as shelltime-daemon.bak rather than shelltime-daemon. This PR mirrors that pattern in the Homebrew path, making both paths consistent in their treatment of the daemon. That consistency is good.

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Summary

Area	Assessment
Code quality	Good — follows existing script style
Error handling	Needs improvement on mv failure
Security	No concerns
Logic / correctness	Correct for the happy path
Test coverage	macOS Homebrew path not exercised by CI (pre-existing gap)

The change is small, purposeful, and addresses a real user pain point. Adding error handling on the mv calls is the main actionable improvement.

[gemini-code-assist]

Code Review

This pull request updates the installation script to rename existing manual-install binaries to backup files upon a successful Homebrew installation. The review feedback suggests using the force flag with the move command to prevent interactive prompts and recommends verifying the success of the move operation before printing confirmation messages.

[gemini-code-assist]

Use mv -f to ensure the command does not prompt for confirmation (e.g., if the user has an alias like mv -i) and wrap it in an if block to only print the success message if the operation actually succeeds.

Suggested change

	mv "$HOME/.shelltime/bin/shelltime" "$HOME/.shelltime/bin/shelltime.bak"
	echo "Renamed ~/.shelltime/bin/shelltime to shelltime.bak (now using Homebrew version)"
	if mv -f "$HOME/.shelltime/bin/shelltime" "$HOME/.shelltime/bin/shelltime.bak"; then
	echo "Renamed ~/.shelltime/bin/shelltime to shelltime.bak (now using Homebrew version)"
	fi

[gemini-code-assist]

Use mv -f to avoid interactive prompts and only print the success message if the command succeeds.

Suggested change

	mv "$HOME/.shelltime/bin/shelltime-daemon" "$HOME/.shelltime/bin/shelltime-daemon.bak"
	echo "Renamed ~/.shelltime/bin/shelltime-daemon to shelltime-daemon.bak (now using Homebrew version)"
	if mv -f "$HOME/.shelltime/bin/shelltime-daemon" "$HOME/.shelltime/bin/shelltime-daemon.bak"; then
	echo "Renamed ~/.shelltime/bin/shelltime-daemon to shelltime-daemon.bak (now using Homebrew version)"
	fi