Record session ID

[dannykopping]

See https://www.notion.so/coderhq/AI-Bridge-Session-Tracking-2f7d579be59280799a61e04d34005a5a?source=copy_link

Claude Code and Codex send through "session" IDs which indicate that an interception belongs to a conversation (series of related requests/responses) within that tool.

Acceptance criteria:

• Session ID is determined from all interceptor implementations (where available)
  • Messages
  • Chat Completions
  • Responses
• Recorder types updated
• Tests added