--show-all-files flag to avoid preview_moves truncation

[djanatyn]

When previewing changes with more than 5 files going into a particular folder, the remaining files will be truncated with some ... and <n> more text:

./target/release/neatcli organize /tmp/neatcli-test-showallfiles
→ Scanning /private/tmp/neatcli-test-showallfiles (organizing by type)...
Preview:
────────────────────────────────────────────────────────────
  Documents (10 files)
    → file2.txt
    → file3.txt
    → file1.txt
    → file4.txt
    → file5.txt
    → ... and 5 more
  Images (8 files)
    → image8.jpg
    → image7.jpg
    → image6.jpg
    → image4.jpg
    → image5.jpg
    → ... and 3 more
────────────────────────────────────────────────────────────
Summary: 18 files to move (0 B)
ℹ Use --execute to execute these changes.

This was hard-coded into the program in src/core/organizer.rs:preview_moves, and using the --verbose flag didn't show the rest of the files:

// Show first 5 files in each folder
for mv in files.iter().take(5) {
    let from_name = mv.from.file_name().unwrap_or_default().to_string_lossy();
    println!("    {} {}", "→".dimmed(), from_name);
}

if files.len() > 5 {
    println!("    {} ... and {} more", "→".dimmed(), files.len() - 5);
}

This PR adds a new --show-all-files flag to neatcli organize:

❯ ./target/debug/neatcli organize --help
Organize files by type or date

Usage: neatcli organize [OPTIONS] [PATHS]...

Arguments:
  [PATHS]...  Target directories to organize (supports multiple paths) [default: .]

Options:
      --by-type                    Organize files by their type (Images, Documents, Videos, etc.)
      --by-date                    Organize files by date (YYYY/MM structure)
      --by-extension               Organize files by extension
      --by-camera                  Organize images by camera model (from EXIF data)
      --by-date-taken              Organize images by date taken (from EXIF data, more accurate)
      --by-artist                  Organize audio files by artist (from ID3/audio tags)
      --by-album                   Organize audio files by album (Artist/Album structure)
  -n, --dry-run                    Preview changes without executing (default behavior)
  -e, --execute                    Actually execute the changes
  -I, --ignore <IGNORE>            Patterns to ignore (can be specified multiple times)
      --min-size <MIN_SIZE>        Minimum file size to include (e.g., 1MB, 10KB, 1G)
      --max-size <MAX_SIZE>        Maximum file size to include (e.g., 100MB, 1GB)
      --after <AFTER>              Only include files modified after this date (YYYY-MM-DD)
      --before <BEFORE>            Only include files modified before this date (YYYY-MM-DD)
  -v, --verbose                    Enable verbose output
  -c, --copy                       Copy files instead of moving
  -q, --quiet                      Suppress all output except errors
  -r, --recursive                  Scan subdirectories recursively
      --startswith <STARTSWITH>    Filter files starting with string
      --endswith <ENDSWITH>        Filter files ending with string (before extension)
      --contains <CONTAINS>        Filter files containing string
      --regex <REGEX>              Filter by regex pattern
      --mime <MIME>                Filter by MIME type (e.g., "image/*", "application/pdf")
      --content <CONTENT>          Filter files containing this text in their content (TXT, MD, JSON, etc.)
      --template <TEMPLATE>        Custom destination template (e.g., "{year}/{month}/{category}/{filename}")
      --on-conflict <ON_CONFLICT>  How to handle file conflicts (skip, overwrite, rename, ask) [default: rename]
      --show-all-files             Show all files in each folder
  -h, --help                       Print help
  -V, --version                    Print version

When used, it will show all the files being moved instead of just the first 5:

./target/release/neatcli organize /tmp/neatcli-test-showallfiles --show-all-files
→ Scanning /private/tmp/neatcli-test-showallfiles (organizing by type)...
Preview:
────────────────────────────────────────────────────────────
  Documents (10 files)
    → file2.txt
    → file3.txt
    → file1.txt
    → file4.txt
    → file5.txt
    → file7.txt
    → file6.txt
    → file10.txt
    → file8.txt
    → file9.txt
  Images (8 files)
    → image8.jpg
    → image7.jpg
    → image6.jpg
    → image4.jpg
    → image5.jpg
    → image1.jpg
    → image2.jpg
    → image3.jpg
────────────────────────────────────────────────────────────
Summary: 18 files to move (0 B)
ℹ Use --execute to execute these changes.

I'm not sure if adding a new flag is appropriate here - maybe we could instead modify the behavior of the --verbose flag? I was surprised when passing --verbose didn't show all the files being changed.

[fognil]

Thanks for the contribution! Clean and well-scoped change.

One minor thought: could also consider exposing --show-all-files on quick and profile run commands in a follow-up,
since they also truncate at 5 files. But not a blocker.

LGTM, merging!