feat: better session creation handling

src/app.rs

@@ -27,7 +27,7 @@ use crate::settings::{
 use iced::widget::{markdown, scrollable};
 use iced::{Size, Subscription, Task, keyboard, window};
 use rfd::AsyncFileDialog;
-use std::collections::VecDeque;
+use std::collections::{HashMap, VecDeque};
 use std::fs;
 use std::path::PathBuf;
 use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
@@ -55,6 +55,9 @@ pub(crate) struct App {
     preference_error: Option<String>,
     selected_project: Option<i32>,
     selected_session: Option<i32>,
+    /// Unsaved sessions, keyed by project. A draft only becomes a `sessions` row
+    /// when its first chat turn is stored, so empty ones vanish on restart.
+    drafts: HashMap<i32, String>,
     choosing_folder: bool,
     pending_project_path: Option<PathBuf>,
     project_name_input: String,
@@ -163,7 +166,8 @@ pub(crate) enum Message {
     CancelProject,
     SelectProject(i32),
     DeleteProject(i32),
-    CreateSession,
+    CreateSession(i32),
+    DiscardSession(i32),
     SelectSession(i32, i32),
     DeleteSession(i32),
     ShowChat,
@@ -204,6 +208,7 @@ impl App {
                         preference_error: None,
                         selected_project: None,
                         selected_session: None,
+                        drafts: HashMap::new(),
                         choosing_folder: false,
                         pending_project_path: None,
                         project_name_input: String::new(),
@@ -275,6 +280,7 @@ impl App {
             preference_error: None,
             selected_project: None,
             selected_session: None,
+            drafts: HashMap::new(),
             choosing_folder: false,
             pending_project_path: None,
             project_name_input: String::new(),
@@ -675,6 +681,7 @@ impl App {
                             for session_id in checkpoint_ids {
                                 let _ = fs::remove_file(session_checkpoint_path(session_id));
                             }
+                            self.drafts.remove(&project_id);
                             if self.selected_project == Some(project_id) {
                                 self.selected_project = None;
                                 self.selected_session = None;
@@ -689,7 +696,8 @@ impl App {
                     }
                 }
             }
-            Message::CreateSession => self.create_session(),
+            Message::CreateSession(project_id) => self.create_session(project_id),
+            Message::DiscardSession(project_id) => self.discard_session(project_id),
             Message::SelectSession(project_id, session_id) => {
                 if self.generating && self.selected_session != Some(session_id) {
                     self.error =