fix: restore cached network sidebars immediately

crates/tinyclient/src/gui/sidebar.rs

@@ -96,6 +96,7 @@ pub struct State {
     muted_open: bool,
     /// The network home on show: what chatd said, and the user's folds.
     pub home: home::Home,
+    saved_homes: HashMap<Network, home::Home>,
     home_list: ListState,
     home_items: Rc<Vec<home::Item>>,
     /// The home's Unread segment, and how many rows it holds.
@@ -165,6 +166,7 @@ impl State {
             muted_news: Vec::new(),
             muted_open: false,
             home: home::Home::default(),
+            saved_homes: HashMap::new(),
             home_list: list_state(cx),
             home_items: Rc::new(Vec::new()),
             home_unread: false,
@@ -319,9 +321,7 @@ impl Shell {
             }
         }
         let home_network = mode.network().filter(|_| matches!(mode, Mode::Network(_)));
-        if home_network != state.home.network {
-            state.home = home_network.map(home::Home::for_network).unwrap_or_default();
-        }
+        state.home.switch_network(home_network, &mut state.saved_homes);
         state.mode = mode;
         state.cursor = None;
         state.drill = None;
@@ -338,7 +338,8 @@ impl Shell {
         hub.watch_rows(WATCH, [], cx);
         self.show_mode(cx);
         self.rebuild_inbox(cx);
-        self.load_directs(cx);
+        // Navigation reads immediately; only background event bursts are debounced.
+        self.load_home(cx);
     }
 
     fn here(&self) -> Location {

crates/tinyclient/src/gui/sidebar/home.rs

@@ -5,7 +5,7 @@
 //! mixed, so the list is a GPUI `list` whose heights are known from each item's kind.
 
 use protocol::{Badge, Conversation, Folder, Key, Network, Space, Special};
-use std::collections::HashSet;
+use std::collections::{HashMap, HashSet};
 use std::rc::Rc;
 
 /// Discord DMs before "Show n more" (product rulings: 10).
@@ -118,6 +118,24 @@ pub struct Home {
 }
 
 impl Home {
+    /// Save the outgoing home and restore the destination without waiting for chatd.
+    pub fn switch_network(&mut self, network: Option<Network>, saved: &mut HashMap<Network, Home>) {
+        if self.network == network {
+            return;
+        }
+        let mut outgoing = std::mem::take(self);
+        // An answer started before leaving must never overwrite a restored home.
+        outgoing.epoch += 1;
+        outgoing.loaded = outgoing.loaded_once;
+        outgoing.drilled.clear();
+        if let Some(previous) = outgoing.network {
+            saved.insert(previous, outgoing);
+        }
+        *self = network
+            .map(|n| saved.remove(&n).unwrap_or_else(|| Home::for_network(n)))
+            .unwrap_or_default();
+    }
+
     pub fn for_network(network: Network) -> Home {
         Home { network: Some(network), ..Home::default() }
     }
@@ -367,6 +385,45 @@ mod tests {
             .collect()
     }
 
+    #[test]
+    fn switching_networks_restores_chats_and_folds_without_a_read() {
+        let mut saved = HashMap::new();
+        let mut home = Home {
+            loaded: true,
+            loaded_once: true,
+            chats: vec![chat("club", 0)],
+            chats_all: true,
+            epoch: 7,
+            ..Home::for_network(Network::Signal)
+        };
+        home.switch_network(Some(Network::Discord), &mut saved);
+        assert!(!home.loaded);
+        home.switch_network(None, &mut saved);
+        home.switch_network(Some(Network::Signal), &mut saved);
+        assert!(home.loaded && home.loaded_once && home.chats_all);
+        assert_eq!(home.chats[0].key.id, "club");
+        assert_ne!(home.epoch, 7, "a pre-navigation read must be stale");
+        assert_eq!(shape(&signal(&home), &[]), ["club"]);
+    }
+
+    #[test]
+    fn leaving_a_sublist_restores_the_completed_home_loading_state() {
+        let mut saved = HashMap::new();
+        let mut home = Home {
+            loaded_once: true,
+            loaded: false,
+            drilled: vec![chat("request", 0)],
+            ..Home::for_network(Network::Discord)
+        };
+        home.switch_network(Some(Network::Signal), &mut saved);
+        home.switch_network(Some(Network::Discord), &mut saved);
+        assert!(home.loaded);
+        assert!(home.drilled.is_empty());
+        let epoch = home.epoch;
+        home.switch_network(Some(Network::Discord), &mut saved);
+        assert_eq!(home.epoch, epoch);
+    }
+
     #[test]
     fn dms_show_every_one_with_a_number_then_the_newest_up_to_ten() {
         let mut chats: Vec<_> = (0..14).map(|n| chat(&format!("d{n}"), 0)).collect();

docs/design/polish/02-discord-slack.md

@@ -76,6 +76,12 @@ normal order. A completed empty DM read still shows servers. Once the home has
 loaded, background refreshes keep its existing rows visible, including when
 returning from a sublist.
 
+Network homes are cached for the GUI session: switching back displays saved
+chats and folds immediately, then refreshes from chatd in the background.
+Explicit navigation skips the event-burst debounce. A network opened for the
+first time still waits for its local chat read. Returning from a sublist restores
+the completed home's loading state, including a previously empty home.
+
 ## New tokens
 For reconciliation with `polish/01-system.md`: `LEAD 20` (leading box of every 28 row), `NAME_X 36`, `INDENT_CHILD 12`, `INDENT_SUB 28`; `tag` component (16, r4, 11/500, `text_soft` on `quiet_fill`, which survives here only as the tag fill); `folder_spine` (the folder's own colour at 70%, 3 wide); `sticky_header` (`sidebar` fill, no rule, per C8). **Divergence to reconcile**: C9 puts DMs in homes on 48 rows; Slack DMs stay 28 because they sit in the user's sections beside channels in one `uniform_list` (Slack's own structure, ruling 1). Discord DMs are 48. Glyphs added: mail, phone, radio, image, building-2, calendar, headphones, headphone-off, monitor, eye, list, moon, smile, log-out, external-link, check-check, wifi-off.