Markdown Mint v0.9.0

• Use VS Code's public Language Model API for optional Copilot continuations
  in Markdown prose, fenced code blocks, and Mermaid source. Automatically
  choose an available editor-suitable model and send bounded context around
  the active cursor; keep model consent under VS Code's user-initiated flow.
• After explicit setup, save the non-secret selected model ID/version and
  reacquire only that exact model after restart on debounced real text input;
  recheck public request access before sending.
• Keep suggestions transient until Tab acceptance, preserve existing Markdown
  and source structure, and keep AI requests independent of document save/edit
  queue work. Package one universal VSIX without a bundled Copilot SDK.
• AI suggestions require VS Code 1.91 or newer; ordinary Markdown editing
  remains available at the existing 1.90 engine minimum.