#9081: docs(discord): add proxy configuration guide

Add comprehensive documentation for configuring Discord Gateway with proxy support. ## Background Users behind corporate firewalls or in restricted regions need proxy configuration for Discord Gateway connections. ## Changes - New documentation file: `docs/discord-proxy.md` - Covers SOCKS5, HTTP proxy configurations - Includes examples for Clash Verge and other proxy tools - Troubleshooting guide for common issues (Error 1006) ## Related - Carbon PR: [feat(gateway): add WebSocket agent/proxy support](https://github.com/buape/carbon/pull/352) <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> Adds a new documentation page (`docs/discord-proxy.md`) describing how to route Discord Gateway/WebSocket traffic through proxies (SOCKS5/HTTP), including environment variable/systemd examples and basic troubleshooting guidance. This is intended to help users behind corporate firewalls or restricted networks configure proxy support for Discord connections. <h3>Confidence Score: 3/5</h3> - This PR is low-risk but needs doc integration and accuracy fixes before merge. - Change is documentation-only, but the new page lacks the repo’s standard frontmatter, appears unlinked from docs navigation, and the “recommended” example is Carbon-specific and not runnable/clearly applicable to OpenClaw users. - docs/discord-proxy.md (frontmatter + correctness), docs/docs.json (add navigation entry/link) <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} **Context used:** - Context from `dashboard` - CLAUDE.md ([source](https://app.greptile.com/review/custom-context?memory=fd949e91-5c3a-4ab5-90a1-cbe184fd6ce8)) - Context from `dashboard` - AGENTS.md ([source](https://app.greptile.com/review/custom-context?memory=0d0c8278-ef8e-4d6c-ab21-f5527e322f13)) <!-- /greptile_comment -->