v1.5.3

Fixed

• Preserve destinations created concurrently with create_project(overwrite=False), including
  at atomic publication; decide backup creation under lock for authorized replacements.
• Preserve surviving clip references across transition creation/removal, and allow updating
  a track while retaining its current name without accepting real name collisions.
• Preserve original source bounds when replacing speed maps, including after trim/split,
  retain requested speed precision, and match MLT's per-frame integration and mapping origin.
• Ignore malformed cancellation notifications without ending the MCP session. Schedule legacy
  batch calls through the same bounded cancellation path as individual calls.
• Bound incomplete render-progress lines in memory and resume parsing after oversized lines.
• Apply network policy to decoded remote file: URIs and UNC paths with mixed separators.
• Request explicit RGBA pixels for PNG previews so Windows codec defaults do not shift colors
  in timeremap output; compare real rendered frames with unmapped native references.

Changed

• Reject speed-map replacement when legacy or externally modified maps lack trustworthy source
  bounds. Reject reverse maps landing on source frame zero, where tested MLT integration can
  return an invalid image; retain constant timewarp as the constant-reversal alternative.
• Document MCPB installation and updates, diagnostic/recovery routes, compatibility coverage,
  and the required Windows integration CI gate separately from opt-in local integration.
• Guide editing models to make creative choices within the user's brief, discover effects,
  create projects from a destination folder, and reuse existing authorization for the same action.