[factory] Finish Relay fleet enrollment and spawn reliability follow-ups

[khaliqgant]

Factory intake

Continue the verified Relay fleet work in isolated worktrees. Refresh issue and PR state, extract and independently verify the completed workspace-enrollment-precedence fix into a real branch and PR, inspect the existing #1430 fleet-spawn-confirmation work, confirm PR #1429 status, and reconcile stale tracker items. Coordinate Agent Relay workers across available machines and verify live process, session, and independent test evidence before accepting agent claims. Make changes merge-ready but do not merge from this task.

The complete authorized spec was snapshotted from the read-only Notion mount into a workspace-private Agent Relay channel:

• channel: factory-notion-e1066218-6a2706fe-040ad02a4c
• ordered message ids: 210931294804557824
• encoding: base64-chunks-v1

Join that channel, concatenate the base64 payload from those exact messages in order, decode it to .integrations/notion/pages/3b36800c-1c90-8020-bf04-f857e1066218/content.md, chmod the file 0444, and then apply the SHA-256 gate below. Never copy the contract to GitHub or another public surface.

Treat the mounted page as the execution contract. Preserve every safety gate in it. Do not write back to Notion.
Before executing, SHA-256 hash the mounted file's UTF-8 bytes and refuse the task unless it matches 040ad02a4cbe8e89be49d25040b77ffcb7744d8e06753d3a02355d883a7dd5d2.

Source identity: notion:3b36800c-1c90-8020-bf04-f857e1066218
Source digest: 7581926581fd9a571a4c681ac66386f9b0803c355f9f5f665c5809597c45cfa3

[khaliqgant]

Live exact-path dispatch evidence from the authorized Notion intake:

• Factory requested node kjg-laptop and cwd=/Users/khaliqgant/Sites/khaliq-agents/docs/benchmarks/mail-surface-2026-08-03.
• placement correctly selected kjg-laptop; the agent binding is active there.
• the kjg-laptop broker log recorded the spawn with cwd=None, despite Factory's Relay fleet payload carrying cwd.
• the mounted contract exists on that machine and hashes to the required 8d69fdac50d639a16f3eb6f1ddfa1f11e4f3575b002073786ce40c0e59c00d06.
• Chief sent the worker an explicit mandatory cd correction so tonight's benchmark can proceed.

Please include the dropped cwd transport/handler path in this issue's fleet spawn reliability investigation and add a real-node regression proving an absolute cwd survives placement through broker spawn.