TaskNotes 4.3.48 (Fork)

This release is from the cybersader/tasknotes fork.

Toolbar buttons disappearing on toggle: Fixed race condition where toggling "Show toolbar buttons" off/on on TaskNotes views caused the "New task" button to vanish. Root causes: (1) old view cleanup removing buttons the new view just injected during Bases re-mount, (2) toggle handler using stale DOM references after YAML save. Now uses deferred cleanup with re-claim detection and YAML-based view type identification instead of fragile DOM class checks.
Docs-builder Mermaid diagrams: Fixed "Syntax error in text" caused by copy-button script appending a <button> child to <pre class="mermaid"> elements, corrupting diagram content. Excluded Mermaid blocks from copy-button injection.
Duplicate toolbar buttons on table views: Made button injection idempotent — always cleans up existing buttons before inserting new ones to handle Bases DOM reuse.

Docs-builder: added Mermaid diagram support (CDN rendering, dark/light theme integration, dedicated CSS).
Docs-builder: added callout/admonition rendering with icons for note, tip, warning, caution, and abstract types.
New development docs: architecture overview, testing guide, writing-docs guide.