- HEADING_REGEX now requires a space/EOL after '#' so tag lines
(#project ...) are no longer misdetected as headings and corrupted.
- Command enable/disable settings now take effect immediately via
checkCallback/editorCheckCallback instead of requiring a reload.
- New Adjacent File auto-increments (Untitled.md, Untitled 1.md, ...)
instead of throwing once Untitled.md already exists.
- Selection-change tracking is delegated from document instead of a
one-time .cm-content scan, so editors opened after startup are covered.
See CHANGELOG.md for details.
