fix: make bin/log compatible with Bash 3.2 on macOS (closes #1440)

[markshust]

Summary

bin/log used the mapfile builtin (Bash 4+), which fails on stock macOS (Bash 3.2) with bin/log: line 44: mapfile: command not found (#1440).

This replaces mapfile with portable constructs:

• All-logs branch: while IFS= read -r loop
• Specific-files branch: a direct for loop building the path array

The latter also fixes a latent bug — the old generate_logs_file_path helper echo'd all paths onto one space-separated line, so multiple file args (bin/log system.log cache.log) collapsed into a single tail argument even on Bash 4. The now-unused helper was removed.

Testing

• bash -n compose/bin/log passes
• No Bash 4+ features remain; all constructs work on Bash 3.2

Closes #1440

🤖 Generated with Claude Code

[what-the-diff]

PR Summary

• Simplified log file path generation
  The function generate_logs_file_path, which was used to create log file paths based on a container log path, is removed. This simplification makes it easier to track and handle log files.

• Improved help commands implementation
  We've updated how -h and --help commands handle mapfile by replacing it with a loop. This loop draws from get_all_logs_file_path to store log file paths in the all_logs_file_path array. This ensures smoother assistance when needed.

• Enhanced logs file path creation with additional parameters
  In instances where extra parameters are passed, we've modified the log file path generation. We've replaced mapfile with a loop that constructs logs_file_path by directly concatenation CONTAINER_LOG_PATH with the provided file names. This change boosts flexibility in inputting file names into the system.