feat: session manger (#867)

* feat: init session manger

* feat: persist selected app to localStorage

- Save app selection when switching providers
- Restore last selected app on page load

* feat: persist current view to localStorage

- Save view selection when switching tabs
- Restore last selected view on page load

* styles: update ui

* feat: Improve macOS Terminal activation and refactor Kitty launch to use  command with user's default shell.

* fix: session view

* feat: toc

* feat: Implement FlexSearch for improved session search functionality.

* feat: Redesign session manager search and filter UI for a more compact and dynamic experience.

* refactor: modularize session manager by extracting components and utility functions into dedicated files.

* feat: Enhance session terminal launching with support for iTerm2, Ghostty, WezTerm, and Alacritty, including UI and custom configuration options.

* feat: Conditionally render terminal selection and resume session buttons only on macOS.

src-tauri/src/session_manager/mod.rs

@@ -0,0 +1,60 @@
+pub mod providers;
+pub mod terminal;
+
+use serde::Serialize;
+use std::path::Path;
+
+use providers::{claude, codex};
+
+#[derive(Debug, Clone, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SessionMeta {
+    pub provider_id: String,
+    pub session_id: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub title: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub summary: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub project_dir: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub created_at: Option<i64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub last_active_at: Option<i64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub source_path: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub resume_command: Option<String>,
+}
+
+#[derive(Debug, Clone, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SessionMessage {
+    pub role: String,
+    pub content: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub ts: Option<i64>,
+}
+
+pub fn scan_sessions() -> Vec<SessionMeta> {
+    let mut sessions = Vec::new();
+    sessions.extend(codex::scan_sessions());
+    sessions.extend(claude::scan_sessions());
+
+    sessions.sort_by(|a, b| {
+        let a_ts = a.last_active_at.or(a.created_at).unwrap_or(0);
+        let b_ts = b.last_active_at.or(b.created_at).unwrap_or(0);
+        b_ts.cmp(&a_ts)
+    });
+
+    sessions
+}
+
+pub fn load_messages(provider_id: &str, source_path: &str) -> Result<Vec<SessionMessage>, String> {
+    let path = Path::new(source_path);
+    match provider_id {
+        "codex" => codex::load_messages(path),
+        "claude" => claude::load_messages(path),
+        _ => Err(format!("Unsupported provider: {provider_id}")),
+    }
+}