Issue #16 - [FEATURE] Show Total Size of Selected Files in Footer

[codepath-open-source-ci]

Current Behavior

The explorer footer shows the count of selected items but not their total size. Users cannot easily determine how much space the selected files occupy without checking properties individually or doing mental math.

Reproduction Steps:

1. Open Puter and navigate to a folder
2. Create several files of different sizes (or use existing files)
3. Select multiple files by clicking while holding Ctrl (or Cmd on Mac)
4. Look at the footer at the bottom of the window
5. Observe: Footer shows "X items selected" (or similar)
6. Observe: No information about the total size of the selected files are displayed

Expected Behavior

When files are selected, the footer should display the total cumulative size of all selected items in human-readable format (e.g., "3 items selected • 45.2 MB").

Acceptance Criteria:

• Footer displays total size when one or more files are selected
• Size is shown in human-readable format (B, KB, MB, GB, TB) with appropriate precision
• Format should be clear, e.g., "3 items selected • 45.2 MB" or "3 items selected (45.2 MB)"
• Size updates dynamically as files are selected/deselected
• Folders count toward item count but their size calculation can be simplified (0 or not included in size)

Steps To Test

1. Open Puter and create test files (note the size of each file)
2. Select one of the files in Explorer
3. Verify footer shows something like:
   "1 item selected • {file_size}"
4. Add another file to selection (Ctrl+Click or Cmd+Click or hold shift + arrow key)
5. Verify footer updates to: "2 items selected • {file)_size}" and that the total file size value is correct
6. De-select one of the files and verify total_size is properly subtracted

Submission

Download https://cap.so/ to record your screen (use Studio mode). Export as an mp4, and drag and drop into an issue comment below.

Guide to submitting pull requests: https://hackmd.io/@timothy1ee/Hky8kV3hlx