When a role participates for the first time (e.g. committer), it previously
only received the system prompt + last step output, missing the full thread
history. This caused hallucination as the role had to guess what happened.
Changes:
- build-continuation-prompt.ts: detect first-time roles and include all
steps' meta + content for last 2-3 steps (within quota)
- context.ts: add isFirstVisit detection helper
- types.ts: add isFirstVisit field to AgentContext
- hermes.ts: pass isFirstVisit through to prompt builder
Fixes#473
xiaoju