ci: add GitHub Actions workflows with semantic-release auto-versioning

chore: fix all 702 clippy warnings across codebase
- auto-fix 475 via cargo clippy --fix
- fix remaining 227 manually: uninlined_format_args, redundant_closure, match_same_arms,
  underscore_binding, format_push_string, items_after_statements, needless_pass_by_value,
  clone_on_copy, case_sensitive_extension, single_match/let-else, write_with_newline,
  and other clippy lints

src/tool/git_cred.rs

@@ -48,11 +48,11 @@ impl Tool for GitCred {
             .arg("credential")
             .arg(operation)
             .output()
-            .map_err(|e| anyhow!("git credential failed: {}", e))?;
+            .map_err(|e| anyhow!("git credential failed: {e}"))?;
         if output.status.success() {
             let stdout = String::from_utf8_lossy(&output.stdout).to_string();
             let stderr = String::from_utf8_lossy(&output.stderr).to_string();
-            Ok(format!("{}{}", stdout, stderr))
+            Ok(format!("{stdout}{stderr}"))
         } else {
             let stderr = String::from_utf8_lossy(&output.stderr).to_string();
             anyhow::bail!("git credential '{}' failed: {}", operation, stderr.trim())