refactor: restructure workspace file organization (#121) (#122)

## Path Changes
- audit.log: memory/audit.log → log/audit.log
- projects.json: memory/projects.json → projects/projects.json
- prompts: roles/<project>/<role>.md → projects/prompts/<project>/<role>.md

## Files Updated
- lib/audit.ts - new audit log path
- lib/projects.ts - new projects.json path
- lib/dispatch.ts - new prompt instructions path
- lib/tools/project-register.ts - prompt scaffolding path
- lib/setup/workspace.ts - workspace scaffolding paths
- lib/context-guard.ts - projects.json path
- lib/tools/setup.ts - tool description
- lib/templates.ts - AGENTS.md template path references

## Documentation Updated
- README.md
- docs/ARCHITECTURE.md
- docs/ONBOARDING.md
- docs/QA_WORKFLOW.md
- docs/ROADMAP.md
- docs/TESTING.md

Addresses issue #121

lib/templates.ts

@@ -144,9 +144,9 @@ Workers call \`work_finish\` themselves — the label transition, state update,
 
 The response includes \`tickPickups\` showing any tasks that were auto-dispatched. Post announcements from the tool response to Telegram.
 
-### Role Instructions
+### Prompt Instructions
 
-Workers receive role-specific instructions appended to their task message. These are loaded from \`roles/<project-name>/<role>.md\` in the workspace (with fallback to \`roles/default/<role>.md\`). \`project_register\` scaffolds these files automatically — edit them to customize worker behavior per project.
+Workers receive role-specific instructions appended to their task message. These are loaded from \`projects/prompts/<project-name>/<role>.md\` in the workspace. \`project_register\` scaffolds these files automatically — edit them to customize worker behavior per project.
 
 ### Heartbeats