The onboarding paywall wrote `dialog-header`, a class no stylesheet
defines, so its close button stacked under the title instead of sitting
beside it. The session-delete confirm buttons had the same problem, and a
`message-entry` wrapper added in August had quietly killed the
`.message + .message` spacing rule in the main chat.
Fixes all three against the patterns already in the codebase, then adds a
contract test so the next undefined class fails instead of shipping: it
scopes itself to our own class families so Tailwind utilities stay out,
strips CSS comments before deciding what counts as defined, and carries
an allowlist of the fifteen deliberate no-op modifiers that must shrink
rather than grow.
Also collapses the paywall's duplicate display heading into the intro
sentence, leaving one heading in the dialog.
BUG-434, BUG-435, BUG-436.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0155nFCgCHtoA7jhSDGmZmMu
Jesse_Chen
0044d4f358