Restore Markdown list markers - #811

Context

Tailwind's base reset sets ul and ol to list-style: none. The Markdown stylesheet adds indentation but does not restore the top-level marker type, so valid lists render without bullets or numbers.

Changes

Restore native list styling only inside .markdown-body, using the same list-style: revert approach already used by the embed stylesheet.

User impact

Ordered and unordered markers are visible again in rendered gist Markdown. Lists elsewhere in the interface are unchanged.

Verification

• Chrome 152 against the production CSS bundle: base computed ol=none; ul=none; this branch computes ol=decimal; ul=disc.
• npx vite -c public/vite.config.js build — passed.
• Embedded Go build — passed.
• golangci-lint run --timeout=20m --disable=errcheck — 0 issues.
• Go format/module checks and translation validation — passed with no additional diff.
• Full SQLite Go suite executed. It is not green on Windows because of existing file-handle cleanup, symlink-privilege, and Git default-branch assumptions; representative failures reproduce on untouched origin/master.

Before	After

Fixes #793