Changelog: vibe-landing v1

Standards-compliance pass (AGENTS.md sections 3 and 5)

Done in place on the latest version. No change to design, copy or product behaviour that was reviewed.

URLs and history

• Unknown routes and record ids show a "Page not found" view instead of silently landing on home or search.
• Empty-hash and sign-in redirects now replace history (no Back trap).
• Search tabs, search text and filters are in the URL (?q=…, replace, debounced). Detail tabs, wizard steps and dialogs use ?tab=, ?step=, ?modal= (push).
• Hub sections, communities and conversations have URLs (#/hub/feed, #/hub/communities/c1).
• Signed-out #/hub and #/account redirect (replace) to #/signin?next=… and return after sign-in. The demo session moved to sessionStorage.
• Navigation controls are real <a href> links (nav, back links, cards, menu, buttons that only navigate). Modified clicks open new tabs.
• Per navigation: document.title, focus to <h1>, scroll top / restore on Back and Forward, aria-current. Smooth scroll respects reduced motion.

Accessibility

• One <main>, banner, navigation and contentinfo landmarks; skip link.
• Heading outline repaired without visual change (levels via aria-level, one h1 per view).
• AA contrast: --sage-deep darkened, gold text on white, placeholders; two-tone focus ring (old citrine ring was 2.2:1).
• Labels and names for form fields, icon-only buttons, switches, toggles (aria-expanded, aria-current).
• Dialogs: role=dialog, focus in, inert background, Tab wrap, Esc closes, focus returns to trigger.
• Live regions for chat, toasts and typing; Esc closes the menu popover.
• prefers-reduced-motion stops all animation and transitions.

Responsive and touch

• Interactive elements are at least 44 px; no horizontal scroll at 320 px (search tabs, sign-in field, filters, chat send).

Where: small labelled edits in the bundle (router, link tags, tab/step state) plus the "STANDARDS PATCH" <style> and <script> blocks at the end of <body>.

• Let's AI page: its visible title is exposed as the single h1 (via the patch layer, no visual change); hub rail headings sit at level 2.