Price graph: technical indicators + zoom presets

[claudiodekker]

Adds toggleable technical-indicator overlays to the item price graph (an EMA trend cloud and a Bollinger cloud) plus Day (24h) and 8h range presets. The indicators make it easy to see at a glance whether an item is trending, crashing, or ranging, so you can time entries and avoid buying into a falling price.

What's new

Indicators toggled with the EMA / BB buttons on the graph (off by default):

• EMA trend cloud: the filled area between a fast (12h) and slow (24h) exponential moving average of the mid-price. It's green when the fast EMA is above the slow (uptrend) and red when below (downtrend), and the band's thickness reflects momentum, pinching to nothing at each crossover where the trend flips. This replaces the usual two-line EMA display with a single, direction-colored signal you don't have to interpret.
• Bollinger cloud: a single band on the mid-price with upper / middle / lower lines (middle = 24h moving average, upper/lower = ±2 standard deviations). Its width shows recent volatility; price near the lower edge is relatively cheap, near the upper edge relatively expensive.

Zoom presets:

• New Day (last 24h) and 8h buttons alongside the existing Week/Month, anchored on the most recent price.

Behaviour & polish:

• Indicator windows are time-based (a fixed real-time span), so they read consistently at every zoom level. The graph automatically computes on 5-minute data when zoomed in and hourly data when zoomed out.
• Indicator colours are editable in the graph settings panel (defaults use a Tailwind palette: green-500 / red-500 / slate-400). Toggle state persists across sessions.

How to read it

• Green cloud + price at the lower Bollinger edge → good buy setup.
• Red cloud + price falling → downtrend, don't buy into it.
• Thin Bollinger cloud = calm/stable (reliable flips); fat cloud = volatile (more upside and more risk).

[cbrewitt]

Runelite recently started reviewing plugin hub pull requests with an LLM which has a 200K token limit for the whole codebase. As we're already very close to the limit, our priority is to reduce the size of the codebase so I don't think we can justify adding the indicators. Additional analysis tool from now on would be better put on the website.

The new zoom presets sounds like a good idea though, and could actually reduce the codebase size if accompanied by a refactor. It looks like there's currently some duplicated code for each preset.