fix(evidence): disclose HIL metal run path; correct POSIX runner profile claims

[ramen-implementer]

Summary

Closes two evidence/claim-honesty findings from review.

1. HIL metal graduation now discloses its run path

Standalone golden-machine PASS/METAL stays legitimate (valid per EVIDENCE_LEVELS.md when RAMEN_HIL_GRADUATION=1 + live serial + target-emitted provenance markers), but per-gate HIL evidence JSON now carries:

• claim_path — operator-golden-machine vs appliance-mediated (plus appliance-live / operator-live / development-log-replay / qemu-or-scaffold for non-graduation paths).
• an appliance object (controller id, target id, controller evidence/log refs, power events) populated only when RAMEN_HIL_APPLIANCE=1.

So a standalone run can no longer be silently read as appliance-mediated S13 graduation. claim_path is also required by a doctrine check in the gate, tying the doc to the code. Previously the appliance evidence fields documented in EVIDENCE_LEVELS.md were never emitted at all.

2. POSIX runner default profile is honestly reported

The default posix_run_v0_sandboxed profile is host-portable-rlimits-only (seccomp=false namespaces=false chroot=false rlimits=true). Seccomp/namespace/chroot helpers remain implemented + unit-tested in sandbox.rs but are not wired into the default path (not portable on unprivileged CI). The security doc previously overclaimed "actual enforcement" for all three, and the S7 gate only grepped a blanket Sandbox: ENABLED log string.

Now: the runtime logs the real control state, a unit contract locks the profile, the S7 gate asserts the actual seccomp=false namespaces=false chroot=false rlimits=true string, and POSIX_RUNNER_SECURITY.md / SECURITY_STATUS.md correct the claims (risk restored to HIGH). DECISIONS.md records both decisions (chosen/rejected/gate) and tracks wiring real enforcement in as future work behind a portable pre-exec design.

Validation

• cargo fmt --all -- --check
• just foundry-org-governance-g0
• just hil-appliance (new per_gate_evidence_contract step)
• just foundry-s7-posix-runner-security (new Test 4 honesty check + Test 4b unit contract)

Notes

• Opened by ramen-implementer[bot] (A2); awaiting a different identity (A3) to approve + merge per separation of duties.
• OS-code change (.rs / .sh), so the foundry job runs under the path-scoped merge-gate.

[maxwellsantoro]

A3 approval. Both findings independently verified closed (HIL claim_path disambiguation + POSIX profile honesty; code/gate/docs three-way consistent). Full Foundry suite green on CI (foundry PASS 6m26s, merge-gate PASS). Separation held: opened by ramen-implementer[bot] (A2), approved by a different identity.