feat(integrations): add create integration review request API and UI

Add a new Tauri command and front-end flow to create PRs/MRs.
The backend builds and validates provider-specific payloads and
endpoints, sends creation requests, and parses responses into the
app's review model. A Svelte dialog and a JS wrapper wire the UI to the
command so users can create requests from the Review Center.

- Implement provider payload and endpoint logic with unit tests
- Expose create_integration_review_request as a Tauri command
- Add CreateReviewDialog UI and integrate a creation button in Review Center

src-tauri/src/integrations/creation.rs

@@ -0,0 +1,105 @@
+use super::*;
+
+fn creation_payload(provider: &str, source: &str, target: &str, title: &str, description: &str) -> Result<serde_json::Value, String> {
+    if title.trim().is_empty() || source.trim().is_empty() || target.trim().is_empty() {
+        return Err("Title, source branch and target branch are required.".into());
+    }
+    if source == target { return Err("Source and target branch must be different.".into()); }
+    Ok(match provider {
+        "github" | "gitea" => serde_json::json!({"head":source,"base":target,"title":title,"body":description}),
+        "gitlab" | "gitlab-self-hosted" => serde_json::json!({"source_branch":source,"target_branch":target,"title":title,"description":description}),
+        "azure-devops" => serde_json::json!({"sourceRefName":format!("refs/heads/{source}"),"targetRefName":format!("refs/heads/{target}"),"title":title,"description":description}),
+        _ => return Err("Unsupported integration provider.".into()),
+    })
+}
+
+fn creation_endpoint(provider: &str, base: &str, repository: &IntegrationRepository) -> Result<reqwest::Url, String> {
+    let base = if provider == "github" { github_api_base_url(base)? } else { normalized_base_url(base)? };
+    let mut url = reqwest::Url::parse(&format!("{base}/")).map_err(|e| e.to_string())?;
+    {
+        let mut path = url.path_segments_mut().map_err(|_| "Invalid integration URL.")?;
+        path.pop_if_empty();
+        match provider {
+            "github" | "gitea" => {
+                let parts: Vec<_> = repository.full_name.split('/').collect();
+                if parts.len() != 2 || parts.iter().any(|part| part.is_empty() || *part == "." || *part == "..") {
+                    return Err("Invalid repository name.".into());
+                }
+                if provider == "gitea" { path.extend(["api", "v1"]); }
+                path.push("repos").extend(parts).push("pulls");
+            }
+            "gitlab" | "gitlab-self-hosted" => { path.extend(["api","v4","projects", &repository.id,"merge_requests"]); }
+            "azure-devops" => { path.extend(["_apis","git","repositories", &repository.id,"pullrequests"]); }
+            _ => return Err("Unsupported integration provider.".into()),
+        }
+    }
+    if provider == "azure-devops" { url.query_pairs_mut().append_pair("api-version", "7.1"); }
+    Ok(url)
+}
+
+#[tauri::command]
+pub async fn create_integration_review_request(provider: String, base_url: String, username: String, token: String, repository: IntegrationRepository, source_branch: String, target_branch: String, title: String, description: String) -> Result<IntegrationReviewRequest, String> {
+    tauri::async_runtime::spawn_blocking(move || {
+        if token.trim().is_empty() { return Err("No token is stored for this integration.".into()); }
+        let source = source_branch.trim().strip_prefix("refs/heads/").unwrap_or(source_branch.trim());
+        let target = target_branch.trim().strip_prefix("refs/heads/").unwrap_or(target_branch.trim());
+        let payload = creation_payload(&provider, source, target, title.trim(), &description)?;
+        let endpoint = creation_endpoint(&provider, &base_url, &repository)?;
+        let client = client()?;
+        let request = client.post(endpoint).header(USER_AGENT, "Gitty").header(ACCEPT, "application/json");
+        let request = match provider.as_str() {
+            "github" => request.bearer_auth(&token),
+            "gitea" => request.header("Authorization", format!("token {token}")),
+            "gitlab" | "gitlab-self-hosted" => request.header("PRIVATE-TOKEN", &token),
+            "azure-devops" => request.basic_auth(if username.is_empty() { "gitty" } else { &username }, Some(&token)),
+            _ => unreachable!(),
+        };
+        // Never automatically retry creation: a lost response can still mean the PR was created.
+        let response = request.json(&payload).send().map_err(|_| "The creation response could not be received. Check the original repository before trying again.".to_string())?;
+        if !response.status().is_success() { return Err(response_error(response, &provider)); }
+        let mut value: serde_json::Value = response.json().map_err(|_| "The request was created, but its response could not be read. Refresh the Review Center before trying again.".to_string())?;
+        let mut review = match provider.as_str() {
+            "github" => {
+                value["pull_request"] = serde_json::json!({});
+                value["repository_url"] = serde_json::json!(format!("{}/repos/{}", github_api_base_url(&base_url)?, repository.full_name));
+                parse_github_review(&value).ok_or("Could not read the created PR.")?
+            }
+            "gitea" => {
+                value["pull_request"] = value.clone();
+                value["repository"] = serde_json::json!({"id":repository.id.parse::<u64>().unwrap_or_default(),"full_name":repository.full_name});
+                parse_gitea_review(&value).ok_or("Could not read the created PR.")?
+            }
+            "gitlab" | "gitlab-self-hosted" => parse_gitlab_review(&value, &provider),
+            "azure-devops" => parse_azure_review(&value, &repository),
+            _ => unreachable!(),
+        };
+        review.repository_name = repository.full_name;
+        review.source_branch = source.to_string();
+        review.target_branch = target.to_string();
+        Ok(review)
+    }).await.map_err(|e| format!("Could not create review request: {e}"))?
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn creation_payloads_and_validation() {
+        for provider in ["github", "gitea", "gitlab", "gitlab-self-hosted", "azure-devops"] {
+            assert!(creation_payload(provider, "main", "main", "Test", "").is_err());
+            assert!(creation_payload(provider, "topic", "main", " ", "").is_err());
+        }
+        assert_eq!(creation_payload("github", "feature/test", "main", "Test", "Body").unwrap()["head"], "feature/test");
+        assert_eq!(creation_payload("gitea", "topic", "main", "Test", "Body").unwrap()["body"], "Body");
+        assert_eq!(creation_payload("gitlab-self-hosted", "topic", "main", "Test", "").unwrap()["source_branch"], "topic");
+        assert_eq!(creation_payload("azure-devops", "topic", "main", "Test", "").unwrap()["targetRefName"], "refs/heads/main");
+    }
+    #[test]
+    fn creation_urls_preserve_prefixes_and_encode_paths() {
+        let repository: IntegrationRepository = serde_json::from_value(serde_json::json!({"id":"17","name":"repo","fullName":"owner/repo","description":"","cloneUrl":"","sshUrl":"","webUrl":"","updatedAt":"","private":false})).unwrap();
+        assert_eq!(creation_endpoint("github", "https://github.com", &repository).unwrap().as_str(), "https://api.github.com/repos/owner/repo/pulls");
+        assert_eq!(creation_endpoint("gitea", "https://git.example/sub", &repository).unwrap().path(), "/sub/api/v1/repos/owner/repo/pulls");
+        assert_eq!(creation_endpoint("gitlab", "https://git.example", &repository).unwrap().path(), "/api/v4/projects/17/merge_requests");
+        assert_eq!(creation_endpoint("azure-devops", "https://dev.azure.com/org", &repository).unwrap().as_str(), "https://dev.azure.com/org/_apis/git/repositories/17/pullrequests?api-version=7.1");
+    }
+}