[FedyaLight]

Stacked on fix/camera-xml-sidecars, whose timeline recognition this
extends.

Final Cut Pro 10.6 and later export FCPXML as a .fcpxmld bundle: a
directory whose Info.fcpxml is the document. Align did not recognize the
extension, and input expansion scanned the bundle as a folder of media, so
adding one ended in "No readable audio or video media was found."

Reading:

• A .fcpxmld directory is a timeline. Reading it and listing its sequences
  use its Info.fcpxml. Errors (ImportError::naming), warnings and the
  draft's source name the bundle the user added, not Info.fcpxml.
• FCPXML media URLs relative to the document now resolve against its folder,
  which for a bundle is the bundle root, and are percent-decoded. Before,
  they resolved against the working directory (for plain .fcpxml files
  too), so a bundle carrying ./Media/… found no media.
• Input expansion treats a bundle as one timeline; an explicit timeline input
  may be a bundle directory. Folder scans do not enter bundles, so media
  inside one are not loose clips.

Repaired copies (Path Fixer, align-cli fixed copies):

• A .fcpxmld destination is written as a bundle: a copy of the source
  bundle (symbolic links kept as links on Unix, folder permissions kept) with
  its document rewritten. It is built in a temporary folder beside the
  destination. An existing destination must itself be a bundle; it is moved
  aside, the new bundle takes its place, and the old one is moved back if
  that fails, so no failure loses either. This also avoids renaming a
  directory onto an existing path, which Windows does not allow.
• The destination may neither lie inside the source (its document or a
  nested bundle) nor contain it, compared as resolved paths.
• Copying checks cancellation per entry and before the swap.
• Relative media URLs that would no longer resolve from the copy's location
  become absolute file URLs; those pointing into a bundle that is copied
  along stay relative (Relocation in rewrite_media_paths).
• A .fcpxml destination receives the repaired document alone.
• docs/formats.md lists bundle import.

Tests, each checked by removing the corresponding fix:

• fcpxml_bundles_are_read_through_their_document
• bundle_media_resolve_against_the_bundle,
  fcpxml_media_may_be_relative_to_the_document (core)
• repaired_bundle_copies_keep_the_bundle (copied files, replaced stale
  bundle, unchanged source, no leftovers beside it)
• repaired_copies_keep_relative_media_resolving
• repaired_bundles_never_overwrite_the_source_or_other_folders (document
  inside the source, nested bundle, source inside the destination, a
  non-bundle folder)
• a_cancelled_bundle_copy_leaves_the_destination
• bundle_copies_keep_symbolic_links (Unix)
• fcpxml_bundles_beside_media_are_imported_as_timelines,
  folder_scans_do_not_enter_fcpxml_bundles

Not changed: an FCPXML document without a sequence still reports "No FCP 7
XML sequence was found" (the existing wording for both XML formats), and the
Path Fixer still appends a missing extension after the save panel returns.

Validation:

• cargo fmt --all -- --check
• cargo clippy --locked --workspace --all-targets -- -D warnings
• cargo test --locked --workspace: 386 passed, 1 ignored