feat: bundle TWZRD pre-sign x402 hook and verify proxy env forwarding

[twzrd-sol]

Python tools using their own x402 client currently have no bundled pre-sign wash hook. Add clawrouter_hermes.twzrd.create_before_sign_hook() and register the accompanying twzrd-before-sign skill through the existing plugin context. Installing the skill alone does not intercept payments: the tool must register the callback on its actual async x402 client.

The optional [twzrd] extra supports Python 3.11+ without changing base plugin dependencies or Python requirements. It uses the official x402 before-payment lifecycle and refuses flagged, unknown, partial, stale, or unavailable merchant-card evidence. Full negative wash evidence permits continuation; it is not a general merchant safety judgment. The intel service receives the selected payee and normal connection metadata.

Proxy environment forwarding already exists via dict(os.environ) into Popen; regression tests now cover explicit TWZRD_AUTO_GATE/TWZRD_FAIL_OPEN propagation and unchanged unset defaults. No redundant supervisor code or default-policy change. Reused/external proxies require their own configuration, and forwarding does not prove that the Node gate package resolved or activated. API-key billing and arbitrary Python tools remain outside this hook.

Validation:

• Full suite: 142 passed, 4 skipped (existing optional/live/sibling checks).
• Real EVM and SVM SDK signing: refusal calls the signer zero times; full negative evidence signs once. Allowed SVM client signature cryptographically verified with offline RPC fixtures.
• HTTP 402 transport refuses without paid retry and preserves PaymentAbortedError as the wrapped cause.
• Fresh wheel install with [twzrd], dependency compatibility check, packaged helper/skill smoke test passed.
• Brand-numbers and diff checks passed; dedicated optional-extra CI job added.

The extra pins solana==0.36.10: 0.40.3 removes the synchronous RPC module x402 imports, while 0.36.6 conflicts with x402's solders requirement. No payments broadcast, runtime deployment, or independent adoption claimed.