Fix issue where command history added to shell was incompatible with fish format, corrupting history

[mooz]

Fix fish shell history format handling

Problem

The current implementation corrupts the fish shell history file by appending commands in an incorrect format. The fish shell history file uses a YAML-like format rather than simple newline-separated entries.

Solution

Implemented shell-specific handlers to properly read and write to each shell's history file according to its specific format.

Changes

• Created a ShellHistoryHandler interface
• Implemented a SimpleHistoryHandler class for basic shells (bash, sh, ksh, tcsh)
• Implemented a ZshHistoryHandler class for zsh (handling timestamp format)
• Implemented a FishHistoryHandler class for fish (handling YAML-like format)
• Updated main functions to use the appropriate handler based on the detected shell

Testing

• Verified history files are correctly updated after command execution in bash, zsh, and fish shells
• Specifically confirmed the fish shell history file is no longer corrupted

[steve8708]

thanks @mooz - looks like build not passing though