aibridge: Implement Bring Your Own Keys (BYOK)

[evgeniy-scherbina]

RFC issue: #1394

Steps:

• implement for Anthropic provider
• implement OpenAI, copilot providers
• manually test multiple clients (claude-code, codex, copilot, etc...)
• change header name in AIBridgeProxy
• Implement second requirement from RFC: Key-type identifier in observability data
  • DB
  • Structured Logs
  • Metrics
• Update documentation how to use different clients (claude-code, codex, etc...)
  • claude-code and codex
  • other clients

Related PRs:

• feat: aibridge BYOK for Anthropic aibridge#216
• feat: aibrige BYOK for OpenAI aibridge#227
• feat: aibridge BYOK coder#23013
• feat: chatgpt provider aibridge#232
• feat: add chatgpt provider for aibridge coder#23755
• feat: add chatgpt support for aibridge coder#23822
• feat: add chatgpt support for aibridge proxy coder#23826

[mtojek]

Hey @evgeniy-scherbina , since coder/coder#23013 was merged, could you update the checkboxes above? I'm wondering how much work is left.

[evgeniy-scherbina]

@mtojek I updated issue with relevant info, I'd say mostly hard work was done, so we should be on track to finish everything by Tuesday.