bug: CSA git guard blocks local-gate fixture git init

[aider4ryder]

The injected CSA git guard rejects git init --quiet as an unknown command, so Mempal local gate receipt tests cannot run inside a guarded session.

Reproduction:

• session ID: 01KZPW16MPVXYCBFTYHYKGFBQS
• session dir: /home/obj/.local/state/cli-sub-agent/home/obj/project/github/RyderFreeman4Logos/mempal/sessions/01KZPW16MPVXYCBFTYHYKGFBQS
• command: just local-gates
• exit code: 101
• failing test: tests/local_gate_receipt_scripts.rs

Stderr excerpt:

CSA git-guard: blocked command: git <command> <option>
Use a hermetic local bare fixture under $CSA_SESSION_DIR/git-fixtures and push to its direct canonical path or file:// URL.

The guard wrapper whitelist is_safe_local_command omits init, while this test needs a temporary local repository before it can exercise the receipt script. Adding init to the local-only allowlist should preserve the no-push policy.