Agents read stale architecture docs -- need Soil-based reference data

## Problem

When nims dispatch work to agentclaudecode, the agent reads docs (architecture.md, INTEGRATIONS.md) from its stale filesystem workspace. This caused Nightwatch to miss Rootlet/Sediment/Fossil definitions during an audit.

## Proposed solution

Index nimsforest2 docs into Soil via Fossil (bedrock -> Fossil -> Soil). Extend gatherContext() to read catalog.docs.* so architecture docs are injected into agent prompts fresh from Soil. Agent workspace stays writable for code work.

## Blocked on

- nimsforest2 repo configured as bedrock source
- Fossil indexes docs/ into Soil
- gatherContext() includes catalog.docs.* keys