Implement LoRA tag extraction in /sdapi/v1/txt2img and /sdapi/v1/img2img API endpoints.

[JackBinary]

Problem

The sd-server ignores <lora:name:weight> tags in prompts sent via the /sdapi/v1/txt2img and /sdapi/v1/img2img API endpoints.

LoRA tags work correctly in the CLI (sd-cli) because it calls extract_and_remove_lora() on every generation. However, the server only calls this function once at startup when parsing command-line arguments. When handling API requests, the server copies default_gen_params, updates the prompt, but never re-parses the new prompt for LoRA tags.

Solution

This patch adds extract_and_remove_lora() to the sdapi_any2img handler function, which services both txt2img and img2img endpoints. The fix clears any pre-existing LoRA data and extracts LoRA tags from the incoming prompt, matching the behavior of the CLI.

[wbruna]

This is unsafe to enable as-is, since it'd allow loading arbitrary server files (see #1156 and #830 ).