Add a Fal-AI inference provider adapter [#3601116]

Problem/Motivation

Add a Fal-AI inference provider adapter to `ai_provider_huggingface`, so configured models can be served by Fal-AI, Part of the configurable Inference Provider routing effort (blocked by the base framework issue).

Steps to reproduce

Proposed resolution

HuggingFace Providers

Remaining tasks

User interface changes

API changes

Data model changes

Issue fork ai_provider_huggingface-3601116

Show commands

Start within a Git clone of the project using the version control instructions.

Add & fetch this issue fork’s repository

Or, if you do not have SSH keys set up on git.drupalcode.org:

Add & fetch this issue fork’s repository

3601116-add-a-fal-ai changes, plain diff MR !22
Check out this branch for the first time

Check out existing branch, if you already have it locally