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/app/bgbash/control.rs

@@ -1,3 +1,4 @@
+#![allow(clippy::cast_possible_truncation, clippy::cast_sign_loss, clippy::cast_precision_loss, clippy::cast_possible_wrap)]
 //! Global registry of running background bash jobs, and control operations
 //! (output polling, kill) exposed to the rest of the app.
 //!
@@ -57,7 +58,7 @@ pub fn bash_output(id: &str) -> Option<Vec<String>> {
 /// Return: `Ok(())` on success, `Err` if the lock is poisoned or no job
 /// with that id exists.
 pub fn bash_kill(id: &str) -> anyhow::Result<()> {
-    let mut map = bash_jobs_map().lock().map_err(|e| anyhow::anyhow!("lock error: {}", e))?;
+    let mut map = bash_jobs_map().lock().map_err(|e| anyhow::anyhow!("lock error: {e}"))?;
     let job = map.remove(id);
     match job {
         Some(job) => {
@@ -70,6 +71,6 @@ pub fn bash_kill(id: &str) -> anyhow::Result<()> {
             }
             Ok(())
         }
-        None => anyhow::bail!("bash job '{}' not found", id),
+        None => anyhow::bail!("bash job '{id}' not found"),
     }
 }