feat(ai-gateway): Update load balancing capabilities documentation for AI Gateway 2.0

[tomek-labuk]

Description

Notes:

• I have no idea how to handle examples for load balancing algorithms for Model
• Do we need a separate reference for load balancing?
• Is model documentation getting too heavy?
• Model documentation still needs to be aligned with UI, it's heave on the API spec side

Preview Links

Checklist

• Tested how-to docs. If not, note why here.
• All pages contain metadata.
• Any new docs link to existing docs.
• All autogenerated instructions render correctly (API, decK, Konnect, Kong Manager).
• Style guide (capitalized gateway entities, placeholder URLs) implemented correctly.
• Every page has a description entry in frontmatter.
• Add new pages to the product documentation index (if applicable).

[Copilot]

Pull request overview

This PR updates the AI Gateway documentation to reflect the AI Gateway 2.0 load balancing workflow (Model entity-based configuration) while preserving legacy AI Proxy Advanced plugin-based guidance for existing deployments.

Changes:

• Updates the /ai-gateway/load-balancing/ reference to describe Model entity load balancing (config.balancer / target_models) and adds a legacy algorithms section behind a <details> block.
• Adds a new include containing the legacy (plugin-based) load balancing algorithms table.
• Expands the Model entity reference with a clearer capabilities table, a deeper TOC, and new per-algorithm Model entity examples.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 6 comments.

File	Description
app/ai-gateway/load-balancing.md	Reframes load balancing docs around Model entities (AI Gateway 2.0) and nests legacy plugin guidance.
app/_includes/ai-gateway/load-balancing/legacy-algorithms.md	Adds a legacy, plugin-focused algorithms table for older configurations.
app/_ai_gateway_entities/model.md	Enhances the Model entity reference (capabilities table, TOC depth, and new algorithm examples).

[Copilot]

Fixed in 9f9206c — removed the redundant "Retry and fallback scenarios" heading and folded the intro text under the single "Retry and fallback scenarios for Model entities" heading.

[CLAassistant]

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✅ tomek-labuk
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