Add LM Studio backend support

[hackall360]

Summary

• add a dedicated codex-lmstudio crate with alias resolution, readiness checks, and default model wiring
• expose the LM Studio backend across the CLI and TUI, documenting the supported architectures and usage
• add integration coverage for LM Studio aliases and include the new backend in the workspace configuration

Testing

• cargo test -p codex-lmstudio
• cargo test -p codex-exec --test all suite::lmstudio::exec_resolves_lmstudio_model_aliases -- --test-threads=1
• cargo test -p codex-tui

---

https://chatgpt.com/codex/tasks/task_b_68d7b97a01c4832f838e912807a17559

[chatgpt-codex-connector]

💡 Codex Review

codex-extended/codex-rs/lmstudio/src/lib.rs

Lines 167 to 191 in 41a7e2a

	fn model_available(payload: &JsonValue, target_model: &str) -> bool {
	fn matches_entry(entry: &JsonValue, target: &str) -> bool {
	let normalized_target = target.trim().to_ascii_lowercase();
	let short_target = target
	.trim()
	.rsplit('/')
	.next()
	.map(str::to_ascii_lowercase)
	.unwrap_or_else(|| normalized_target.clone());
	let check = |candidate: &str| {
	let normalized_candidate = candidate.trim().to_ascii_lowercase();
	normalized_candidate == normalized_target
	|| normalized_candidate == short_target
	|| normalized_candidate.ends_with(&short_target)
	};
	entry
	.get("id")
	.and_then(|v| v.as_str())
	.map(check)
	.or_else(|| entry.get("name").and_then(|v| v.as_str()).map(check))
	.or_else(|| entry.get("model").and_then(|v| v.as_str()).map(check))
	.or_else(|| entry.as_str().map(check))
	.unwrap_or(false)

[P1] Readiness check misses LM Studio models with quantization suffixes

The model_available probe only considers a model present when id, name, or model exactly match the canonical identifier or end with the short name. LM Studio’s /v1/models responses commonly append quantization info to the identifier (e.g. Meta-Llama-3.1-8B-Instruct-Q4_0). Such IDs neither equal the canonical value nor end with it, so ensure_lmstudio_ready will error even when the requested model is installed, preventing the CLI/TUI from starting. Consider matching by substring or prefix rather than strict equality/ends_with to accept IDs with additional suffixes.

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting

• @codex fix this CI failure
• @codex address that feedback