fix(server): staged AGENTS.md carries macOS paths on the Linux hub — the ×4 /Users/aaron hardcode (standalone, #852 audit finding)

[aarontrowbridge]

Problem

The audit (#850 lens 0b, standalone finding): the live hub's staged AGENTS.md — the system prompt every session on erlich reads — hardcodes macOS paths (/Users/aaron/…, ×4 occurrences) on a Linux hub. Agents following the workflow literally resolve wrong paths (the staged bundle's own home is /home/aaron/…). It predates the Aug-28 role move to erlich and survived it.

Approach

Find the staged server AGENTS.md's source root in this repo (the staging pipeline's source of record — not the deployed copy at ~/.amico/server/…), fix the four /Users/aaron/… occurrences to the platform-correct paths (or to the config-derived home resolution the rest of the bundle uses), and add the deployment-side check that would have caught it: the staging build (or the doctor) asserts the staged AGENTS.md contains no /Users/ paths when the target host is Linux. Deploy the fixed staging on erlich after merge.

Acceptance criteria

• Zero /Users/aaron occurrences in the staged AGENTS.md source in this repo.
• A test pins the invariant: the staged AGENTS.md source renders with platform-correct paths (hermetic — the fixture is the file itself; a /Users/ path on a Linux-targeted staging fails the check).
• The deployed staging on erlich refreshed from the fixed source (manual deploy step, verified by grepping the live file).

Source

Part of #852 (the audit's standalone bug — fixable independently of the sunset itself). No blockers.

[aarontrowbridge]

Integrated into the campaign's integration branch (PR #1672, merge 39d7879): the guard test landed (37/0 targeted; integration tree extension suite 3692/0). Recorded finding: the ×4 paths were already scrubbed by #856 — the slice's real delta was guarding ops/server/hub-AGENTS.md (uncovered by #856's scan). Closing per the pack: sub-issues close at integration-branch merge.