[P2] a11y/discoverability bundle in Pages library + toolbar

[MhaWay]

From a hands-on ggally.net build session:

1. PageCard delete/rename live ONLY in a right-click context menu (no visible affordance; keyboard users cannot open it at all). WP list shows inline links; Elementor library shows action buttons.
2. Page cards are with nested block content (h3/p inside button = invalid nesting, no focus outline).
3. Toolbar title input has no accessible name (label 'Page title' missing; getByRole('textbox', {name:/title/}) finds nothing).
4. Sidebar block buttons carry the glyph letter in the accessible name ('A Accordion', 'I Icon List'), which breaks exact-name automation and reads awkwardly in screen readers - keep the letter visual-only (aria-hidden).
5. 'Page' starter is described as 'A standard page to build freely' but actually creates a page pre-filled with section+heading+text.

[MhaWay]

Partial: #33 added the Built-with-Blocky admin badge and made Edit-with-Blocky the primary row action, which fixes discoverability for built pages in the WP list. Remaining open: library context menu without right-click, PageCard nesting, toolbar title aria-label, glyph letters in accessible names, starter not empty.