Add checkout compliance and run traceability to all agents

Add explicit POST /api/issues/{issueId}/checkout and PATCH status
update curl templates with X-Paperclip-Run-Id headers to all agent
heartbeats. Document Gemini workspace sandboxing in Hugh's TOOLS.md.
Also removed Regina's ghost instructionsFilePath from live DB.

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

marketing/samuel/HEARTBEAT.md

@@ -25,12 +25,34 @@ Then orient yourself:
 
 For each assigned issue:
 
+#### Checkout the issue first
+
+**You MUST checkout before doing any work. If you skip this, your work is untraceable.**
+
+    curl -sf -X POST "$PAPERCLIP_API_URL/api/issues/{issueId}/checkout" \
+      -H "Authorization: Bearer $PAPERCLIP_API_KEY" \
+      -H "Content-Type: application/json" \
+      -H "X-Paperclip-Run-Id: $PAPERCLIP_RUN_ID" \
+      -d '{"agentId": "a413e3b4-14c8-45bc-b732-439d6e296dde", "expectedStatuses": ["todo", "backlog", "blocked"]}'
+
+Replace `{issueId}` with the actual issue ID. If checkout returns 409 (already claimed), skip to the next issue — never retry.
+
+#### Do the work
+
 - Read the full thread including any context the CMO provided
 - Determine which mode you're in: **content writing**, **social media**, or **community**
 - Execute the work (see mode-specific rules below)
 - Open a PR to `privilegedescalation/marketing` with your output
-- Comment on the Paperclip issue with the PR link and a one-line summary
-- Mark the issue in-progress, or done if fully resolved
+
+#### Update issue status
+
+**Every status change MUST include the X-Paperclip-Run-Id header.**
+
+    curl -sf -X PATCH "$PAPERCLIP_API_URL/api/issues/{issueId}" \
+      -H "Authorization: Bearer $PAPERCLIP_API_KEY" \
+      -H "Content-Type: application/json" \
+      -H "X-Paperclip-Run-Id: $PAPERCLIP_RUN_ID" \
+      -d '{"status": "done", "comment": "PR link and one-line summary."}'
 
 ### 3. If no assigned work — run your scheduled loop