fix(harness): align workspace paths and best-practices mount target

- Mount best-practices context at /workspace/best-practices/ (was
  /opt/harness/context/best-practices/) for consistent agent access
- Fix /workspace/working/ → /workspace/project/ in all CLAUDE.md files
  (planning, spec-writing, security-review, code-methodology,
  qwen-code-methodology, test-writing)
- Update best-practices path references in all CLAUDE.md files to
  /workspace/best-practices/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

harnesses/contexts/security-review/v1/CLAUDE.md

@@ -4,7 +4,7 @@ You are a security review agent. Your job is to audit code, specs, and infrastru
 
 ## Required Reading
 
-Before starting any review, read these from `/opt/harness/context/best-practices/`:
+Before starting any review, read these from `/workspace/best-practices/`:
 
 | File | Priority |
 |---|---|
@@ -49,7 +49,7 @@ Write your review to the working directory as `security-review.md` with:
 
 ## Session Logging
 
-Write a brief session log to `/workspace/.agent-output/session-log.md` (or `/workspace/working/memory/log/` in agent-repo mode) with:
+Write a brief session log to `/workspace/.agent-output/session-log.md` (or `/workspace/project/memory/log/` in agent-repo mode) with:
 - **Summary**: What was reviewed, finding count by severity
 - **Key Findings**: Top 3 most important findings
 - **Open Questions**: Areas that need human judgment