fix(cli): mofa agent logs --limit returns most-recent N lines (tail semantics)

[SH20RAJ]

Summary

Fixes #1298.

mofa agent logs <id> --limit N was returning the first N matching
lines instead of the most-recent N lines, making it behave like
head -n N instead of the expected tail -n N.

Root Cause

display_log_file used an early-break pattern:

// OLD (broken)
if let Some(max) = limit && count >= max {
    break;   // stops reading after N lines from the TOP
}

This exits the read loop after max matches, so only the oldest lines
were ever returned.

Fix

Remove the early break. Collect all filtered lines into a Vec,
then compute the tail with:

// NEW
let start = output_lines.len().saturating_sub(max);
let display_lines = &output_lines[start..];

This is a simple O(file_size) solution: the Vec is already being built
anyway, so there is no extra pass over the data.

Tests

Added test_logs_limit_returns_most_recent_lines which writes five
numbered lines and asserts that --limit 2 yields ["line-4", "line-5"]
and not ["line-1", "line-2"].

cargo test -p mofa-cli commands::agent::logs::tests

Checklist

• Root cause identified and fixed
• Regression test added
• Compiles clean (cargo check -p mofa-cli)
• Fixes mofa agent logs --limit returns earliest lines instead of most recent lines #1298