E9: Player PotM Dominance

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Some players are match-winners. We want to see who dominates games most frequently.

### The Objective
Find out which players have the highest ratio of "Player of the Match" (PotM) awards relative to the number of matches they played.

### Requirements:
1. `matches.csv` contains the `player_of_match` column.
2. `deliveries.csv` contains the information about who actually played in the match (a player played in a match if their name appears anywhere as a batsman, non-striker, or bowler in that `match_id`).
3. Join or aggregate this data to find out how many distinct matches a player participated in.
4. Calculate their "Clutch" Ratio: Isolate matches that were "Playoffs" or "Finals". Calculate the PotM frequency for these high-pressure matches specifically.
5. Calculate the regular ratio: `PotM Awards / Total Matches Played`. Filter out players with less than 20 matches.
6. **Visualization:** Create a **visually appealing grouped bar chart** of the top 15 players featuring the highest regular ratios, contrasting their regular season PotM ratio with their playoff PotM ratio.

### Mandatory Submission Rule:
Submit your solution via a Pull Request. In your PR description, include a screenshot of your generated visualisation, a copy of the core logic code cell, and a **Markdown** summary. Your summary should interpret the bar chart. Who is the most decisive match-winner in IPL history on a per-game basis? Did the results surprise you compared to absolute PotM counts?

Start with matches.csv and deliveries.csv, using player_of_match and the batsman, non-striker, bowler, and match_id fields to determine participation and playoff or final matches. Done means a grouped bar chart of the top 15 regular-ratio players, plus a pull request containing the visualization screenshot, core logic code cell, and Markdown interpretation requested in the issue.

Written by the indexing model from the issue text.