fix(docs): prevent mobile content overflow

[vyctorbrzezowski]

Summary

This prevents docs content from widening the page on narrow mobile viewports.

• Keeps custom table wrappers bounded to the viewport.
• Lets long inline code/config keys wrap instead of expanding the document width.
• Uses fixed table layout on mobile so table cells wrap inside the available width.
• Adds visual smoke coverage for a real long-content page at mobile width.

Behavior notes

The fix is content-agnostic. The repro page used for verification is /channels/discord/ because it currently contains both a responsive table and long inline config keys, including:

voice.realtime.providers.openai.interruptResponseOnInputAudio: false

At 390px viewport width:

• Before: the document widened to 500px, creating horizontal page scroll.
• After: document and body width stay at 390px, and the long inline code wraps inside the viewport.

Visual proof

Same route and 390px viewport, focused around the long inline config key.

Before	After

Full evidence page: https://crisp-petal-g4gd.here.now/

Validation

• git diff --check
• node --check scripts/docs-site/assets.mjs
• node --check scripts/docs-site/smoke.mjs
• node --check scripts/docs-site/visual-smoke.mjs
• npm run docs:build:preview
• node --check dist/docs-site/assets/docs-site.js
• Playwright 390px layout check: document width 390, body width 390, long inline code found and fitting