Add rustfmt configuration and reformat code

- Document new Rust formatting standards in AGENTS, CODE_MAP, and
  PROGRESS.
- Add rustfmt.toml with style 2024, 2‑space indents, 100‑char width, LF
  endings.
- Apply consistent 2‑space indentation and ordering across source files.
- Minor clean‑up of imports and whitespace to match the new style.

src/app/states/skills_config.rs

@@ -1,6 +1,6 @@
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct SkillsConfigState {
-    pub id: usize,
-    pub name: &'static str,
-    pub selected_skill: usize,
+  pub id: usize,
+  pub name: &'static str,
+  pub selected_skill: usize,
 }