feat(web,hub): rich hover tooltips on session-list attention indicators

[heavygee]

Summary

Follow-up to #698 / #699: replace generic native title tooltips on session-list attention dots and the schedule clock with rich, accessible hover copy.

• HoverTooltip — lightweight CSS-driven tooltip primitive (no portal/positioning JS).
• pendingRequests[] on SessionSummary — capped (5), oldest-first structured slice of pending tool requests so permission/input dots can list actual tool names without a per-row detail fetch. Additive; older hubs degrade gracefully.
• Attention dot bodies — permission/input list blocking tools (+ honest +N more overflow when single-kind); background shows task count; unread shows title only (relative time already on the row).
• Schedule clock — hub adds nextScheduledAt (MIN future scheduled_at per session); tooltip shows relative + absolute fire time (e.g. "Fires in 26m · Jun 17, 12:06 PM") and "+N more" when multiple are queued.
• i18n — en + zh-CN for all new strings.

Closes #940

Test plan

• bun run typecheck (cli + web + hub)
• bun test shared/src/sessionSummary.test.ts
• npx vitest run web/src/components/SessionAttentionIndicator.test.tsx
• npx vitest run web/src/lib/scheduledTime.test.ts
• bun test hub/src/store/messages.test.ts (batch minFutureScheduledAtBySessionIds)
• Manual: hover permission/input/background/unread dots — tooltip names the reason
• Manual: hover schedule clock — shows countdown + absolute fire time
• Manual: session with 2+ scheduled messages — "Next … · +N more"

Made with Cursor

[github-actions]

Findings

• [Major] Tooltip content is not reachable from keyboard focus — the new tooltip puts aria-describedby/aria-label on an inner non-focusable <span>, while the actual focus target is the outer session-row <button> in SessionList.tsx. Because focus stays on the button, group-focus-within on this descendant never matches, and screen readers focus the button without the new tooltip description. This regresses the stated accessible hover-copy path for both attention dots and the schedule clock. Evidence: web/src/components/HoverTooltip.tsx:40 and web/src/components/SessionList.tsx:672.
  Suggested fix:

  // Have the focused row own the description and expose a parent-focus trigger.
  <button
      type="button"
      aria-describedby={tooltipId}
      className="group/session-row ..."
  >
      ...
      <HoverTooltip
          id={tooltipId}
          label={scheduledLabel}
          target={<ScheduleIcon className="h-3.5 w-3.5 text-[var(--app-hint)]" />}
          revealOnParentFocusClass="group-focus-visible/session-row:opacity-100 group-focus-visible/session-row:visible"
      >
          ...
      </HoverTooltip>
  </button>

Questions

• None.

Summary

• Review mode: initial
• One accessibility regression found in the new tooltip primitive/usage. Residual risk: I did not run the full test suite in this automation pass.

Testing

• Not run (automation)

HAPI Bot

[github-actions]

Findings

• No issues found.

Questions

• None.

Summary

• Review mode: follow-up after new commits
• No issues found in the latest full PR diff. The previous bot finding about tooltip keyboard/focus ownership appears addressed by moving aria-describedby to the session row and exposing parent focus-visible reveal classes. Residual risk: I did not run the full test suite in this automation pass.

Testing

• Not run (automation)

HAPI Bot