Add cortex-rest-api-pricing-calculator skill

[sfc-gh-nashukla]

Summary

• Adds a new skill for calculating Snowflake Cortex REST API costs (token-based LLM inference endpoint)
• Supports both conversational quick estimates and linking to a published Streamlit interactive app
• Covers all models: Claude, GPT, DeepSeek, Mistral, Llama with prompt caching (Table 6b) and non-caching (Table 6c) rates

What it does

• Quick Estimate mode: CoCo calculates costs inline given model, token volumes, and optional discount
• Interactive App mode: Directs users to a published Streamlit app on Snowhouse with editable rates, PDF viewer, and Excel export
• Includes references/pricing-rates.md with current rate tables from Snowflake Credit Consumption Table

Test plan

• Invoke skill with $cortex-rest-api-pricing-calculator estimate cost for claude-sonnet-4-5
• Verify Quick Estimate calculates correctly (e.g., 300M input × $3.00 = $900)
• Verify Interactive App mode returns the Snowhouse Streamlit URL
• Confirm skill does NOT trigger for Cortex AI SQL function pricing queries

.... Generated with Cortex Code

[sfc-gh-nashukla]

Closing - will resubmit later.