v1.2.0 — richer media authoring + QTI 2.1 export

Richer media authoring (content_slide blocks, per-item images, inline assets), screen reorder, and
QTI 2.1 export. 24 MCP tools. All additive — existing specs unchanged, no server-side LLM.

Added — richer media authoring + screen reorder (W9)

• content_slide multi-block (blocks[]) — optional ordered list of {html} / {asset_id, caption?}
  blocks → interleave paragraph → image → paragraph → image in one screen (no more 3-consecutive-slide
  workaround). Falls back to body_html/media_asset_id when blocks is absent; body_html is now optional.
• Per-item images — optional image_asset_id on accordion and tabs items, on timeline
  events; front_asset_id/back_asset_id on flashcards. All optional/backward-compatible.
• reorder_screens tool (24th MCP tool) — reorder a project's screens to an explicit id order
  (validates the set matches all existing screens). add_screen still appends.
• Inline images in *_html — sanitizer now allows data: URIs on <img> (inline base64
  icons), and {{asset:<id>}} tokens in any *_html interpolate to the packaged asset (self-contained,
  unlike external <img src>). Validator extended to check per-item / block asset references.

Added — QTI 2.1 export (W8a)

• export_qti tool (23rd MCP tool) + core/qti.py: quiz screens → IMS QTI 2.1 assessmentItem
  XML. mcq/true_false → choiceInteraction, fill_blank → textEntryInteraction, with
  correctResponse + standard match_correct response processing. Deterministic XML (lxml), so
  content becomes portable to QTI-compatible systems. Unmappable types are silently skipped (no fake
  conversion); no server-side LLM. Returns {count, items:[{filename, xml}]}. See docs/QTI.md.

Full changelog: https://github.com/kemalyy/edumints-scorm-mcp/blob/main/CHANGELOG.md#120--2026-06-24