Add "Reading Time" and "Progress Percentage" indicators

[saismrutiranjan18]

Given the article's exceptional length (38,000+ words), readers would benefit from knowing their progress and estimated reading time remaining. This is especially important for such a long-form piece.

Proposed features:
Reading time indicator:
Show estimated total reading time at the top (e.g., "~2 hour read")
Display estimated time remaining as user scrolls
Account for interactive modules that take additional time