docs: align model backend tables with the registry

[msluszniak]

Description

Regenerated every Supported Backends cell from models.ts and fixed the rows that disagreed with what the library actually resolves.

Page	Row	Was	Now
LLM	Llama 3.2, Qwen 3, Qwen 2.5, Hammer 2.1, Phi-4 Mini	XNNPACK	XNNPACK, MLX
LLM	Liquid LFM 2.5	one row, credited Vulkan to the text models	split text / VL, Vulkan on VL only
LLM	SmolLM2 135M/360M/1.7B	missing	XNNPACK, MLX
Keypoints	RF-DETR Keypoint	XNNPACK, Core ML, MLX	XNNPACK, Core ML
Text embeddings	multi-qa	one row, credited Core ML to mpnet	split MiniLM / mpnet

After the change every one of the 104 registry models is reachable from a docs row and no cell claims a backend the registry does not ship.

Introduces a breaking change?

• Yes
• No

Type of change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update (improves or adds clarity to existing documentation)
• Other (chores, tests, code style improvements etc.)

Tested on

• iOS
• Android

Testing instructions

Docs only. Backend cells were diffed against models.ts on main by a script, and sizes for the new SmolLM2 and split LFM 2.5 rows come from HEAD on the HuggingFace artifacts at resolve/v0.10.0.

Related issues

#556

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings