Add distill, layered context loading, and smarter retrieval

[JimmyMcBride]

Summary

• add first-class decision notes under .brain/resources/decisions/
• improve retrieval ranking with recency, note-type, and active-session context signals
• add brain search --inject for agent-ready context blocks
• add brain distill --session and brain distill --brainstorm proposal workflows
• add layered context loading with brain context load --level 0..3
• update session closeout to suggest brain distill --session when durable memory updates are missing

Maintainer And Workflow Updates

• update the Brain skill so it teaches distill, search --inject, context load, and the finish-stage recovery flow
• document the standard serial ticket loop for multi-story execution
• require updating skills/brain/SKILL.md when Brain command behavior changes
• document and refresh local Codex/OpenClaw Brain skill installs as part of that workflow

Fixes

• fix Windows CLI JSON normalization so JSON-based CLI tests do not corrupt escape sequences
• fix Windows CLI skill-target assertions to accept native path separators

Verification

• go test ./...
• go build ./...