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/mode/effort.rs

@@ -1,5 +1,6 @@
+#![allow(clippy::cast_possible_truncation, clippy::cast_sign_loss, clippy::cast_precision_loss, clippy::cast_possible_wrap)]
 //! Effort mode: cycles the agent's reasoning effort level, which scales the
-//! LLM's temperature and max_tokens for subsequent turns.
+//! LLM's temperature and `max_tokens` for subsequent turns.
 
 use crate::app::state::rest::AppStateRest;
 
@@ -44,7 +45,7 @@ pub fn cycle_effort(state: &mut AppStateRest) {
     let label = current_effort_str(state);
     state.push_toast(crate::app::state::types::Toast::new(
         crate::app::state::types::ToastKind::Info,
-        format!("Effort: {}", label),
+        format!("Effort: {label}"),
     ));
     state.dirty = true;
 }