CodeAlive Skills v2.0.9

Changes

• Send Accept: application/json, application/problem+json from the CodeAlive context-engine skill client so API ProblemDetails responses are negotiated consistently.
• Update chat continuation example to use the 24-character conversation ID returned by the API.
• Bump plugin version to 2.0.9.

Verification

• python3 -m pytest -q -> 18 passed.