spec: add ohlc-bar specification

[github-actions]

New Specification: ohlc-bar

Related to #3293

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specification.md

ohlc-bar: OHLC Bar Chart

Description

An OHLC (Open-High-Low-Close) bar chart displays financial price data using vertical bars with horizontal tick marks. Each bar shows the price range from high to low as a thin vertical line, with a left tick indicating the opening price and a right tick indicating the closing price. Unlike candlestick charts that use colored bodies, OHLC bars provide a cleaner, less cluttered view favored by technical analysts who prefer to focus on price levels rather than visual patterns.

Applications

• Analyzing daily stock price movements with focus on precise price levels
• Comparing price action across multiple securities on the same chart without color distraction
• Technical analysis where traders prefer bar charts over candlesticks for pattern recognition

Data

• date (datetime) - The time period for each bar (e.g., day, hour, minute)
• open (numeric) - Opening price at the start of the period
• high (numeric) - Highest price during the period
• low (numeric) - Lowest price during the period
• close (numeric) - Closing price at the end of the period
• Size: 20-100 periods for clear visualization
• Example: Daily OHLC prices for a stock over 30-60 trading days

Notes

• Use thin vertical lines for the high-low range
• Horizontal ticks should extend to the left for open and right for close
• Consider using different colors for up bars (close > open) vs down bars (close < open) for easier reading
• Time axis should have appropriate date formatting based on data frequency
• Grid lines help read exact price levels

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Next: Add approved label to the issue to merge this PR.

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