[BUG] Bedrock use now reporting zero costs as of 0.2.85

Environment

• Platform (select one):
• [ ] Anthropic API
• [x] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: <!-- output of claude --version -->
• Operating System: <!-- e.g. macOS 14.3, Windows 11, Ubuntu 22.04 -->
• Terminal: <!-- e.g. iTerm2, Terminal App -->

Bug Description

Bedrock is always reporting $0 costs; it seems this is a regression

Steps to Reproduce

1. Install 0.2.84
2. Run a query
3. /cost
4. See non-zero reported costs
5. Install 0.2.85
6. Repeat
7. See zero reported costs - but they are in fact not free!

Expected Behavior

1. Costs are reported as non-zero, or something else is reported if they are unable to be calculated instead of $0

Actual Behavior

1. Costs are reported as zero
2. I don't think the reported costs were ever precise/accurate for Bedrock, but they were directionally correct / helpful nonetheless. Ideally the costs would actually be calculated correctly for Bedrock, but even using the Anthropic API pricing page as a base (which is what I think it was) is fine

Additional Context

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