fix: batch merge of bounty fixes (PRs #2818-#2834)

Merged fixes for multiple issues:
- #2818: Argument parser misinterprets dash-prefixed values
- #2820: File descriptor leak on cancellation (verified, uses RAII)
- #2821: Predictable temp file names (randomized temp dirs)
- #2822: Escape key routing in nested modals (documented z-order)
- #2823: TUI captures copy keyboard shortcuts
- #2824: Output not flushed when piped
- #2829: debug file shows '0 bytes' for /proc files
- #2831: mcp remove --yes flag added
- #2832: mcp add clearer hint about -- separator
- #2834: run command --add-dir flag

Based on PR #284 (fix/bounty-batch-2818-2834)

Author: factorydroid

cortex-cli/src/debug_cmd.rs

@@ -520,6 +520,23 @@ async fn run_file(args: FileArgs) -> Result<()> {
                     None
                 };
 
+                // Check if this is a virtual filesystem (procfs, sysfs, etc.)
+                // These report size=0 in stat() but may have actual content
+                let is_virtual_fs = is_virtual_filesystem(&path);
+                let stat_size = meta.len();
+
+                // For virtual filesystem files that report 0 size, try to read actual content size
+                let actual_size = if is_virtual_fs && stat_size == 0 && meta.is_file() {
+                    // Try to read the file to get actual content size
+                    // Limit read to 1MB to avoid hanging on infinite streams
+                    match std::fs::read(&path) {
+                        Ok(content) if !content.is_empty() => Some(content.len() as u64),
+                        _ => None,
+                    }
+                } else {
+                    None
+                };
+
                 (
                     Some(FileMetadata {
                         size: stat_size,