add support for system clipboard copy and paste

CHANGELOG.md

@@ -3,18 +3,23 @@ Game store page: https://crispypin.itch.io/marble-machinations
 
 ## [Unreleased]
 ### added
+- OS clipboard copy/paste, with fallback to old behavior when copying
+- in-grid text comments (not yet editable in-game)
 - changelog file
 - (dev) sub-tick visualisation in debug mode
 - (dev) tests and benchmarks
 ### fixed
 - equal comparator did not output one of two incoming signals in some cases, depending on wire length and update order
 ### changed
-- changed: comparators can now power other tiles without a wire between, including other comparators
-- changed: directly moving marbles (to adjactent tile without anything between) now have priority over new marbles being created, instead of the two events cancelling each other
+- made early levels (1-5) easier and more tutorial-like
+- comparators can now power other tiles without a wire between, including other comparators
+- directly moving marbles (to adjactent tile without anything between) now have priority over new marbles being created, instead of the two events cancelling each other
 
 ## v0.2.1 - 2025-03-14
-- added: "Simple comparison" level
-- fixed: phantom marble (empty tile causing other marbles to bounce away) appearing after multiple machines tried to output to the same location at once
+### added
+- "Simple comparison" level
+### fixed
+- phantom marble (empty tile causing other marbles to bounce away) appearing after multiple machines tried to output to the same location at once
 
 ## v0.2.0 - 2024-12-24
 *everything else*