feat(cli): add cost estimation per provider for Goose CLI

[GaryZhous]

Built on top of #2941, this pull request enhances the goose-cli session module by introducing functionality to estimate and display cost information for token usage based on provider pricing data. It includes new methods for normalizing model names, fetching pricing data, and calculating costs, as well as configuration updates to enable cost display. Instead of hard-coding the cost calculation, I make use of Jack's Pricing_Cache which he created in #2992.

Pricing Integration:

• Added initialize_pricing_cache to session startup: Ensures pricing cache is initialized, with error handling to log warnings if initialization fails.
• Introduced estimate_cost_usd function: Calculates token usage cost in USD using provider pricing data and normalized model names.
• Added display_cost_usage function: Displays cost information in USD if pricing data is available, including token breakdown.

Model Name Normalization:

• Implemented normalize_model_name function: Cleans up model names by removing suffixes (e.g., "-latest", date-like patterns) and converting version numbers for compatibility with pricing data. Otherwise we are not able to access the pricing info from the cache since Openrouter does the model naming differently. (e.g. claude-3-5-haiku-latest is claude-3.5-haiku on Openrouter)

Configuration Updates:

• Added configuration parameters: Introduced GOOSE_CLI_SHOW_COST to toggle cost display and GOOSE_PROVIDER to specify the provider name.

These changes collectively improve the goose-cli tool by providing users with detailed cost insights based on their session's token usage. For models whose pricing is unknown, nothing will show up.

How to enable

# one-off
GOOSE_CLI_SHOW_COST=true goose chat

# persistent
# ~/.config/goose/config.yaml
GOOSE_CLI_SHOW_COST: true

After

[lily-de]

This is great. LGTM with one ask -- can you update the docs to include the new variable you introduced? https://github.com/block/goose/blob/main/documentation/docs/guides/environment-variables.md thanks!

[GaryZhous]

@lily-de done!