Clear reachable high-severity runtime advisories

[fettpl]

What changed

• Upgraded the coding CLI to undici@^7.29.0 and minimatch@^10.2.6.
• Upgraded the AI package to proxy-agent@^8.0.2 and removed its unused direct undici declaration.
• Refreshed the direct-owner lock graph to brace-expansion@5.0.9, ip-address@10.4.0, and the current SOCKS proxy stack without dependency overrides.
• Added a high-severity production dependency audit gate to CI.
• Added focused coverage for CLI dispatcher setup, brace-expanded package filters, and loopback Bedrock HTTP/SOCKS proxy transport.

Why

The previous lockfile shipped reachable high-severity advisories in the CLI dispatcher, package-pattern, and Bedrock proxy paths. The direct dependency ranges and stale transitive resolutions retained vulnerable undici, brace-expansion, and ip-address versions; the AI package also declared undici without using it.

Impact

Production installs no longer contain high- or critical-severity advisories reported by npm for these paths. CLI proxy timeouts, package filtering, and Bedrock HTTP/SOCKS proxy behavior remain covered and unchanged.

Checks

• npx tsx ../../node_modules/vitest/dist/cli.js --run test/bedrock-endpoint-resolution.test.ts (8 passed)
• npx tsx ../../node_modules/vitest/dist/cli.js --run test/stdout-cleanliness.test.ts (3 passed)
• npx tsx ../../node_modules/vitest/dist/cli.js --run test/package-manager.test.ts (96 passed)
• npx tsx ../../node_modules/vitest/dist/cli.js --run test/model-resolver.test.ts (39 passed)
• npm run check
• npm audit --omit=dev --audit-level=high with npm 11.19.0 (0 high, 0 critical; moderate-only findings remain outside this issue's gate)
• npm run audit:prod

Fixes #931

Note

Clear high-severity runtime advisories in production dependencies

• Upgrades proxy-agent from v6 to v8 in packages/ai and removes the direct undici dependency to fix a high-severity advisory in the Bedrock proxy dependency chain
• Bumps minimatch and undici in packages/coding-agent to clear high-severity advisories in CLI networking dependencies
• Adds an audit:prod npm script (npm audit --omit=dev --audit-level=high) and a CI step that runs it on every build to catch future high-severity production advisories
• Adds proxy integration tests for Bedrock (HTTP and SOCKS5) and a new CLI test verifying that an EnvHttpProxyAgent with unlimited timeouts is installed before main runs

^{Macroscope summarized cf8c38f.}

[fettpl]

@snimu CI is fully green and independent review found no blocking issues. This is ready for maintainer review. It fixes #931 by upgrading the reachable runtime dependency chains, adding a high-severity production audit gate, and covering HTTP/SOCKS transports end to end.