feat(command-palette): add grouped suggestions, history tracking, and model/provider fuzzy matching

- Export `PaletteGroup` and `PaletteSuggestion` to represent suggestion metadata.
- Implement command history with deduplication, capacity limit, and recent‑command suggestions.
- Enhance dynamic suggestion logic to include history, commands, models, and providers with fuzzy ranking.
- Add UI rendering for grouped suggestions, header with command palette label, and footer instructions.
- Update help text with new shortcuts (Ctrl+P, layout save/load) and expose new agent/layout commands.

crates/owlen-tui/src/commands/mod.rs

@@ -160,6 +160,26 @@ const COMMANDS: &[CommandSpec] = &[
         keyword: "stop-agent",
         description: "Stop the running agent",
     },
+    CommandSpec {
+        keyword: "agent status",
+        description: "Show current agent status",
+    },
+    CommandSpec {
+        keyword: "agent start",
+        description: "Arm the agent for the next request",
+    },
+    CommandSpec {
+        keyword: "agent stop",
+        description: "Stop the running agent",
+    },
+    CommandSpec {
+        keyword: "layout save",
+        description: "Persist the current pane layout",
+    },
+    CommandSpec {
+        keyword: "layout load",
+        description: "Restore the last saved pane layout",
+    },
 ];
 
 /// Return the static catalog of commands.
@@ -168,29 +188,35 @@ pub fn all() -> &'static [CommandSpec] {
 }
 
 /// Return the default suggestion list (all command keywords).
-pub fn default_suggestions() -> Vec<String> {
-    COMMANDS
-        .iter()
-        .map(|spec| spec.keyword.to_string())
-        .collect()
+pub fn default_suggestions() -> Vec<CommandSpec> {
+    COMMANDS.to_vec()
 }
 
 /// Generate keyword suggestions for the given input.
-pub fn suggestions(input: &str) -> Vec<String> {
+pub fn suggestions(input: &str) -> Vec<CommandSpec> {
     let trimmed = input.trim();
     if trimmed.is_empty() {
         return default_suggestions();
     }
-    COMMANDS
+
+    let mut matches: Vec<(usize, usize, CommandSpec)> = COMMANDS
         .iter()
         .filter_map(|spec| {
-            if spec.keyword.starts_with(trimmed) {
-                Some(spec.keyword.to_string())
-            } else {
-                None
-            }
+            match_score(spec.keyword, trimmed).map(|score| (score.0, score.1, *spec))
         })
-        .collect()
+        .collect();
+
+    if matches.is_empty() {
+        return default_suggestions();
+    }
+
+    matches.sort_by(|a, b| {
+        a.0.cmp(&b.0)
+            .then(a.1.cmp(&b.1))
+            .then(a.2.keyword.cmp(b.2.keyword))
+    });
+
+    matches.into_iter().map(|(_, _, spec)| spec).collect()
 }
 
 pub fn match_score(candidate: &str, query: &str) -> Option<(usize, usize)> {
@@ -219,6 +245,19 @@ pub fn match_score(candidate: &str, query: &str) -> Option<(usize, usize)> {
     }
 }
 
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn suggestions_prioritize_agent_start() {
+        let results = suggestions("agent st");
+        assert!(!results.is_empty());
+        assert_eq!(results[0].keyword, "agent start");
+        assert!(results.iter().any(|spec| spec.keyword == "agent stop"));
+    }
+}
+
 fn is_subsequence(text: &str, pattern: &str) -> bool {
     if pattern.is_empty() {
         return true;