V0.99.8

[dwash96]

Addresses:

• RFE: Provide a mechanism to opt-in or opt-out of setting a standard User-Agent header for all LLM API calls made by cecli #496

Includes:

• fix: Handle UnicodeDecodeError in .gitignore files #493
• Allow model overrides and aliases to apply when switching models by making singleton ModelOverrides class
• Add "defaults" key to model-overrides underneath which all settings apply to the un-aliased model key
• Change ShowContext tool name to GetLines so its intent is clearer to LLMs
• Unify ReplaceText, InsertText, and DeleteText into a singular EditText tool
• Add clearer instructions for models on how to handle truncated command outputs