UI tweaks

[Curtis Summers (csummers)]

Summary

This PR delivers a broad UI consistency and accessibility pass across the Hot app, introduces shared design-system primitives, fixes several behavioral UI bugs, and improves expired-session handling.

What changed

Session and refresh behavior

• Added a global private-page fetch guard that detects expired sessions before sign-in HTML can be inserted into partial UI regions.
• Preserved the current page as the post-sign-in next destination.
• Added correct HTMX redirect handling, same-origin credentials, and no-store behavior for dashboard refreshes.
• Loaded refresh/session protection before Alpine and page scripts.
• Added HTTP coverage for expired dashboard and run-detail requests.
• Removed duplicated waiting/execution details from run summaries.

Design-system foundations

• Added canonical .badge-* and .chip components.
• Standardized primary, secondary, and outline-danger button semantics.
• Updated gray-500 to the AA-compliant #767676.
• Removed the global hot-red-500 remapping workaround.
• Normalized remaining CSS and JavaScript color literals.
• Moved agent-graph dark colors onto the shared gray palette.
• Removed stale generated CSS selectors.

UI correctness and accessibility

• Fixed failed runs appearing with success styling.
• Added status-aware event-run badges for succeeded, failed, cancelled, pending-retry, and running states.
• Added rendering regression coverage for all five run statuses.
• Separated confirmation icon severity from destructive action intent.
• Marked all 14 delete, remove, revoke, and deactivate confirmations explicitly destructive.
• Preserved primary styling for Retry/Re-run confirmations and error-alert acknowledgement buttons.
• Restored modal button focus rings and shared button classes.
• Added the ≥100% red state to all seven usage meters.
• Changed missing-context-variable links from destructive to secondary actions.
• Improved contrast, focus treatments, checkbox accents, text-size floors, labels, help text, placeholders, and empty states.
• Removed duplicate headings and assorted spacing/layout vestiges.

Page-family migrations

• Migrated alerts, destinations, channels, subscriptions, and history pages to shared buttons, links, badges, cards, containers, and form conventions.
• Normalized observability lists and table partials across runs, events, streams, tasks, schedules, handlers, MCP services, webhooks, files, and stores.
• Standardized pagination controls, filter focus rings, status colors, and responsive table treatments.
• Migrated keys, service keys, domains, organizations, environments, and context-variable pages.
• Normalized organization, team, billing, account, plan, checkout, and project pages.
• Aligned dashboard widgets, hero metrics, issue panels, detail tabs, modal shells, and shared layouts.
• Consolidated JavaScript status-color mappings and normalized js-* behavior hooks.
• Changed workflow and observability tab accents from purple to Hot red.

Dark mode and documentation

• Restored raised dark-mode panels to gray-800 with gray-700 hairlines.
• Retained gray-900 for inset and recessed surfaces.
• Aligned the docs index, namespace viewer, project docs, source browser, and shared docs styles with the application design system.

Cleanup

• Removed trailing whitespace from the alert-destination templates.
• Regenerated CSS to remove unused shadow-2xl and hover:text-hot-red-600 utilities.