fix: resolve x-forwarded-* hop-aware, right-to-left

[pi0x]

The X-Forwarded-* headers were resolved leftmost-first, so under the recommended trustProxy: "loopback" an attacker sending X-Forwarded-For: 9.9.9.9 got request.ip === "9.9.9.9". Because real proxies append to the header, the leftmost value is fully client-controlled — this defeats IP rate-limits, allowlists, geo checks and audit logs (F7). The same class of issue let forwarded proto and host be poisoned (cache keys, password-reset links).

New hop-aware model (D1)

Resolve the forwarded chain hop-aware, right-to-left from the immediate peer, skipping addresses in the trusted set — the first untrusted address is the client. This matches Express (trust proxy), nginx ($proxy_add_x_forwarded_for) and AWS ALB.

• The client is the rightmost address not in the trusted set.
• If every hop is trusted, the leftmost entry is the client.
• If the immediate peer is untrusted, the forwarded headers are ignored entirely.
• The same model gates forwarded proto/host: only the value contributed by the trusted proxy is honored, so a spoofed prefix cannot poison request.url.

Changes

• Replace firstForwardedValue with forwardedList / resolveClientIP / trustedHops / forwardedHopValue in src/_trust-proxy.ts.
• Apply at all three call sites: universal plugin, Node adapter (_node/request.ts + _node/url.ts), and AWS adapter (_aws/utils.ts, starting from the gateway-verified sourceIp as the nearest hop).
• Rewrite the tests that enshrined the old leftmost behavior and add hop-aware cases (spoofed-prefix, all-trusted, untrusted-peer, proto/host poisoning).
• Rewrite the trustProxy docs to state the hop model explicitly (Docs-T1).

Verification

• pnpm vitest run --exclude '**/{deno,bun}*.test.ts' test/ — 860 passed, 32 skipped
• pnpm lint and pnpm typecheck clean

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📥 Commits

Reviewing files that changed from the base of the PR and between f2edab1 and e9bcf32.

📒 Files selected for processing (8)

• docs/1.guide/5.options.md
• src/_trust-proxy.ts
• src/adapters/_aws/utils.ts
• src/adapters/_node/request.ts
• src/adapters/_node/url.ts
• test/aws.test.ts
• test/node-trust-proxy.test.ts
• test/trust-proxy-plugin.test.ts

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/trust-proxy-hop-aware

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commit: e9bcf32