feat(arch): adopt hypermedia & vertical slicing paradigm (Datastar + Deno SSR)

- Establish server-driven hypermedia architecture with Datastar to eliminate brittle imperative client DOM manipulation
- Codify vertical feature slicing (routes, queries, fragments co-located by domain)
- Formalize right-sized dual transport: standard text/html for user mutations, targeted SSE for Valkey pub/sub broadcasts
- Define zero-trust guardrails: untrusted client signals, 16KB payload bounds, rate limiting, and data-ignore subtree protection
- Establish hypermedia error protocol (4xx/5xx return JSX error fragments) and mid-stream SSE resilience
- Add active task checklist with granular 1-to-1 items and shared component suggestions
- Update AGENTS.md with AI-optimized engineering principles (SRP, bounded files, flat call chains, distinctive naming)

tasks/checklist.md

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+# Active Task Checklist
+
+### Sticky Navigation Header
+
+- [ ] `sticky-sub-header-docking`: Dock the sticky `Sessions & Events`
+      sub-header directly beneath the main navigation bar so it scrolls smoothly
+      without overlapping or covering top navigation elements.
+- [ ] `sticky-sub-header-opaque-bg`: Ensure the sticky sub-header has an opaque
+      background so underlying cards do not bleed through on scroll.
+
+### Single Session Creation (DirectPassDrawer)
+
+- [ ] `single-session-form-hiding`: Hide the single session creation form upon
+      minting so only the completed handoff card is displayed.
+- [ ] `single-session-cancel-button-removal`: Remove the Cancel button from the
+      view once a single session has been created.
+- [ ] `single-session-copy-button-styling`: Style the 1-Click Link copy button
+      using the standard outline style matching other copy actions.
+- [ ] `single-session-submit-button-label`: Label the single session drawer
+      submit button as "Create Session".
+- [ ] `single-session-handoff-ok-button`: Label the single session handoff
+      completion button as "OK".
+
+### Multi-Claim Event Creation (WorkshopDrawer)
+
+- [ ] `event-submit-button-label`: Label the multi-claim event drawer submit
+      button as "Create Event".
+- [ ] `event-handoff-ok-button`: Label the multi-claim event handoff completion
+      button as "OK".
+
+### Dropdown Accordion Headers
+
+- [ ] `single-session-accordion-arrow-fix`: Eliminate the broken double arrow
+      (`> >`) from the single session optional settings dropdown header.
+- [ ] `single-session-accordion-label`: Label the single session optional
+      settings dropdown header as "Customize App Permissions & Scopes
+      (Optional)".
+- [ ] `workshop-accordion-arrow-fix`: Eliminate the broken double arrow (`> >`)
+      from the workshop pass optional settings dropdown header.
+- [ ] `workshop-accordion-label`: Label the workshop pass optional settings
+      dropdown header as "Custom Vanity Slug & PIN Code (Optional)".
+
+### Rapid Creation & Tab State
+
+- [ ] `single-session-create-another-button`: Add a "Create Another" button on
+      the single session handoff card that clears the form and starts a new
+      session in one click.
+- [ ] `event-create-another-button`: Add a "Create Another" button on the event
+      handoff card that clears the form and starts a new event in one click.
+- [ ] `handoff-tab-lock-state`: Disable switching between Single Session and
+      Multi-Claim Event tabs while viewing a completed handoff card.
+- [ ] `handoff-tab-unlock-on-reset`: Re-enable tab switching when the user
+      clicks "Create Another" or closes the drawer.
+
+### Expired Events Management
+
+- [ ] `expired-events-query-split`: Separate event passes into active events and
+      expired events based on their expiration timestamp and status.
+- [ ] `expired-events-collapsible-accordion`: Organize expired events into a
+      dedicated collapsible `<details>` section titled "📁 Expired Events (N)"
+      below active events.
+- [ ] `expired-events-card-styling`: Display expired event passes with distinct
+      muted styling and expired status badges.
+- [ ] `expired-events-1click-reopen`: Provide a one-click "+1h Reopen" button on
+      naturally expired events to add time and reactivate them.
+
+### Guest Drawer Telemetry & Sync
+
+- [ ] `guest-drawer-telemetry-backend`: Fetch the last activity action, last
+      activity timestamp, and agent flag for each attendee.
+- [ ] `guest-drawer-last-action-display`: Display the attendee's last recorded
+      action and relative time on their guest card.
+- [ ] `guest-drawer-client-badge`: Display a client icon (such as Web or CLI) on
+      each attendee card based on their recorded action.
+- [ ] `guest-drawer-timer-sync-on-extend`: Dynamically update the countdown
+      timer and expiration time in the open guest drawer when an event is
+      extended.
+
+---
+
+## Suggestions & Architectural Notes (Ideas to Evaluate)
+
+- **Shared Drawer / Form Component Extraction:** The Single Session
+  (`DirectPassDrawer.tsx`) and Multi-Claim Event (`WorkshopDrawer.tsx`) creation
+  forms share many common UI features (app selection dropdown, lifespan preset
+  pills, optional settings accordion, action bars, and handoff cards). Consider
+  consolidating shared form sections or extracting common sub-components to
+  reduce code duplication and ensure consistent state handling.
+- **Unified Handoff Card Pattern:** The post-creation handoff state across both
+  forms follows the exact same pattern (badge header, copy buttons for
+  links/CLI/tokens, and dual `[ Create Another ]` + `[ OK ]` footer). A shared
+  component or common helper could streamline handoff rendering and state resets
+  across both modes.