fix(osd): show "No update is currently available" instead of a perpetual "Checking for updates…"

The Updates tab's idle status was "Checking for updates…", which never resolves: the update model
only tracks positive availability (UpdateState has no "check completed" signal), so on a device
already on the latest version it sat on "Checking…" indefinitely, implying a check that never
finishes. Show a resolved "No update is currently available." instead — the wording the design
already specifies (osd-menu-plan.md §5, "deliberately not a claim that a remote check established
'latest'").

- updateprompt.cpp: kCheckingStatus -> kNoUpdateStatus (both idle call sites).
- updateprompt.hpp: hidden_status_ defaults empty so it falls through to the single kNoUpdateStatus
  source rather than duplicating the literal; ignored/requested states still set their own text.
- main.cpp: the notify-mode startup seed matches, so the seed and first live tick agree (no flicker).

A newer release still shows what's new and the Update-now/Ignore actions, unchanged. Launcher builds
clean, 21 unit tests pass, clang-format-18 clean; independently code-reviewed.

Author: Properrr

CHANGELOG.md

@@ -8,6 +8,12 @@ minor versions may include breaking changes.
 
 ## [Unreleased]
 
+### Fixed
+- **Settings ▸ Updates** no longer sits on "Checking for updates…" forever when you're already on
+  the latest version. That text implied a check that never finishes; it now shows a resolved
+  **"No update is currently available."** (a newer release still shows what's new and the update
+  actions, unchanged).
+
 ## [0.0.5] - 2026-07-15
 
 ### Fixed

launcher/src/main.cpp

@@ -54,7 +54,7 @@ std::string update_policy_status(SelfUpdateMode mode) {
     case SelfUpdateMode::Off:
       return "Updates are off. Update Deckback in Discover or run flatpak update.";
     case SelfUpdateMode::Notify:
-      return "Checking for updates…";
+      return "No update is currently available.";
     case SelfUpdateMode::Auto:
       return "Automatic updates are enabled. New versions install when they are available.";
   }

launcher/src/updateprompt.cpp

@@ -28,7 +28,7 @@ namespace {
 
 constexpr std::size_t kMaxNotesLen = 4000;
 constexpr long kReleasesTimeoutSec = 6;
-constexpr std::string_view kCheckingStatus = "Checking for updates…";
+constexpr std::string_view kNoUpdateStatus = "No update is currently available.";
 constexpr std::string_view kIgnoredStatus =
     "This available version is ignored. A newer version will appear here.";
 constexpr std::string_view kRequestedStatus =
@@ -384,7 +384,7 @@ void UpdatePromptController::tick(bool on_watch) {
   (void)on_watch;
   if (!cfg_.osd) return;
   if (!cfg_.state || !cfg_.state->available()) {
-    feed(false, std::string(kCheckingStatus), "");
+    feed(false, std::string(kNoUpdateStatus), "");
     return;
   }
   const std::string commit = cfg_.state->commit();
@@ -398,7 +398,7 @@ void UpdatePromptController::tick(bool on_watch) {
     if (notify_) kick_changelog();
   }
   if (!notify_) {
-    feed(false, hidden_status_.empty() ? std::string(kCheckingStatus) : hidden_status_, "");
+    feed(false, hidden_status_.empty() ? std::string(kNoUpdateStatus) : hidden_status_, "");
     return;
   }
   const ChangelogView cv = current_changelog();

launcher/src/updateprompt.hpp

@@ -114,10 +114,10 @@ class UpdatePromptController {
   void feed(bool has_update, const std::string& status, const std::string& notes);
 
   UpdatePromptConfig cfg_;
-  DevToolsClient client_;    // input-thread only (the confirm toast)
-  std::string last_commit_;  // last commit tick() reacted to (edge detection)
-  bool notify_ = false;      // an un-ignored update is available
-  std::string hidden_status_ = "Checking for updates…";
+  DevToolsClient client_;      // input-thread only (the confirm toast)
+  std::string last_commit_;    // last commit tick() reacted to (edge detection)
+  bool notify_ = false;        // an un-ignored update is available
+  std::string hidden_status_;  // empty -> the generic "no update" idle status (kNoUpdateStatus)
 
   // Last values fed to the OSD, so tick() only calls set_update_model on a change.
   bool fed_has_ = false;