feat(ai): add AI-assisted commit splitting flow

Introduce a split-planning path for staged changes that asks supported AI
providers to group files into ordered Conventional Commit messages. The
plan is validated before execution so every staged file is assigned once
and unsafe states are rejected.

A new dialog lets users review and adjust the proposed groups before
creating the commits in sequence, with safeguards to preserve remaining
changes if something fails.

src-tauri/crates/commit_ai/src/cloud.rs

@@ -215,6 +215,89 @@ pub async fn review_custom(
     openai_compatible_review_request(url, api_key, model, diff).await
 }
 
+async fn openai_compatible_split_request(
+    url: String,
+    bearer: Option<&str>,
+    model: &str,
+    diff: &str,
+) -> Result<String, String> {
+    let system = "You split staged Git changes into small, logical commits. Return only JSON in this exact shape: {\"summary\":\"...\",\"groups\":[{\"message\":\"type(scope): subject\",\"reason\":\"...\",\"files\":[\"path\"]}]}. Every staged file must appear exactly once. Use only paths from the supplied staged file list. Keep messages in English and use Conventional Commits. Do not use markdown.";
+    let user =
+        format!("Analyze these staged changes and propose an ordered commit plan:\n\n{diff}");
+    let body = OpenAiRequest {
+        model: model.to_string(),
+        messages: vec![
+            OpenAiMessage {
+                role: "system",
+                content: system.to_string(),
+            },
+            OpenAiMessage {
+                role: "user",
+                content: user,
+            },
+        ],
+        temperature: 0.1,
+    };
+    let client = http_client()?;
+    let mut request = client.post(url).json(&body);
+    if let Some(key) = bearer.filter(|key| !key.trim().is_empty()) {
+        request = request.bearer_auth(key);
+    }
+    let response = request
+        .send()
+        .await
+        .map_err(|err| format!("Request to the AI model failed: {err}"))?;
+    let status = response.status();
+    let text = response
+        .text()
+        .await
+        .map_err(|err| format!("Could not read response: {err}"))?;
+    if !status.is_success() {
+        return Err(format!("API error ({status}): {text}"));
+    }
+    let parsed: OpenAiResponse =
+        serde_json::from_str(&text).map_err(|err| format!("Could not process response: {err}"))?;
+    parsed
+        .choices
+        .into_iter()
+        .next()
+        .and_then(|choice| choice.message.content)
+        .map(|content| sanitize_message(&content))
+        .filter(|content| !content.is_empty())
+        .ok_or_else(|| "The model did not return a commit plan.".to_string())
+}
+
+pub async fn split_openai(api_key: &str, model: &str, diff: &str) -> Result<String, String> {
+    if api_key.trim().is_empty() {
+        return Err("OpenAI API key is missing.".to_string());
+    }
+    openai_compatible_split_request(
+        "https://api.openai.com/v1/chat/completions".to_string(),
+        Some(api_key),
+        model,
+        diff,
+    )
+    .await
+}
+
+pub async fn split_custom(
+    base_url: &str,
+    api_key: Option<&str>,
+    model: &str,
+    diff: &str,
+) -> Result<String, String> {
+    if base_url.trim().is_empty() {
+        return Err("Endpoint URL is missing.".to_string());
+    }
+    openai_compatible_split_request(
+        format!("{}/chat/completions", base_url.trim_end_matches('/')),
+        api_key,
+        model,
+        diff,
+    )
+    .await
+}
+
 #[derive(Serialize)]
 struct AnthropicMessage {
     role: &'static str,
@@ -338,3 +421,47 @@ pub async fn review_anthropic(api_key: &str, model: &str, diff: &str) -> Result<
         .filter(|text| !text.is_empty())
         .ok_or_else(|| "The model did not return a review.".to_string())
 }
+
+pub async fn split_anthropic(api_key: &str, model: &str, diff: &str) -> Result<String, String> {
+    if api_key.trim().is_empty() {
+        return Err("Anthropic API key is missing.".to_string());
+    }
+    let system = "You split staged Git changes into small, logical commits. Return only JSON in this exact shape: {\"summary\":\"...\",\"groups\":[{\"message\":\"type(scope): subject\",\"reason\":\"...\",\"files\":[\"path\"]}]}. Every staged file must appear exactly once. Use only paths from the supplied staged file list. Keep messages in English and use Conventional Commits. Do not use markdown.".to_string();
+    let body = AnthropicRequest {
+        model: model.to_string(),
+        max_tokens: 2400,
+        system,
+        messages: vec![AnthropicMessage {
+            role: "user",
+            content: format!(
+                "Analyze these staged changes and propose an ordered commit plan:\n\n{diff}"
+            ),
+        }],
+    };
+    let client = http_client()?;
+    let response = client
+        .post("https://api.anthropic.com/v1/messages")
+        .header("x-api-key", api_key)
+        .header("anthropic-version", "2023-06-01")
+        .json(&body)
+        .send()
+        .await
+        .map_err(|err| format!("Request to Anthropic failed: {err}"))?;
+    let status = response.status();
+    let text = response
+        .text()
+        .await
+        .map_err(|err| format!("Could not read response: {err}"))?;
+    if !status.is_success() {
+        return Err(format!("API error ({status}): {text}"));
+    }
+    let parsed: AnthropicResponse =
+        serde_json::from_str(&text).map_err(|err| format!("Could not process response: {err}"))?;
+    parsed
+        .content
+        .into_iter()
+        .find_map(|block| block.text)
+        .map(|text| sanitize_message(&text))
+        .filter(|text| !text.is_empty())
+        .ok_or_else(|| "The model did not return a commit plan.".to_string())
+}

src-tauri/crates/commit_ai/src/lib.rs

@@ -2,7 +2,7 @@ mod cloud;
 
 pub use cloud::{
     generate_anthropic, generate_custom, generate_openai, review_anthropic, review_custom,
-    review_openai,
+    review_openai, split_anthropic, split_custom, split_openai,
 };
 
 use std::{