v0.23.5: Release 0.23.5 (#43)

• Creates projects on oxframe 0.23.5.
• Six more blocks for oxframe add (24 in all): metric-row (numbers
  counting up side by side), key-combo (a keyboard shortcut pressed key by
  key), steps (numbered steps filling in along a line), social-post
  (author, text and likes counting up), split-screen (two columns with a
  divider) and search-bar (a query typed, results dropping in).
• The agent files mention Project::loudness.
• No ffmpeg installed? oxframe render and oxframe publish download a
  static build once (about 25 MB, checked by SHA-256) into the oxframe cache
  and use it for the project, the preview and video clips. oxframe ffmpeg
  downloads it ahead of time (CI, offline work); OXFRAME_NO_FFMPEG_DOWNLOAD=1
  turns it off. oxframe doctor shows which ffmpeg is used.
• The agent files point to fix in each oxframe check issue: the change
  with the numbers worked out.
• oxframe render --format gif (or --out demo.gif): an animated GIF for a
  README, a pull request or a chat, 720 wide and 15 fps unless --size and
  --fps say otherwise. The MCP render tool takes format: "gif" and fps.