Darkmoon v1.3.1 — Privacy gateway parity for workflows

Darkmoon v1.3.1 extends the Privacy Gateway to the workflow boundary, on top of v1.3.0.

Fixed / Hardened

• Privacy gateway now covers run_workflow. It previously bypassed the gateway that execute_command already used. run_workflow now rehydrates approved placeholders in structured workflow parameters, recursing into nested dicts, lists, tuples and dict keys; rejects unknown placeholders; never restores CRED into workflow parameters; and sanitizes every string in nested workflow results before they return to the model. It accepts a session_id so it shares the caller's session vault.
• Workflow URL exfiltration blocked, matching the raw-command path.

Builds on the default-boundary fix in v1.3.0 (issue #40: URL / DOMAIN / PATH tokenized by default). Privacy + workflow test suite: 33 passed.

Thanks to @luojiyin1987 for the contribution (#41).