Updates: a newer release installs by itself, after a question

With Settings > System > Install updates on By itself (issue #52), a
release found by the daily check is offered once no key was pressed for
2 minutes and nothing would be cut by a restart. The question goes over
whatever App is open, with Cancel and Accept, and installs after 30 s
without an answer. Each update that held, and each one undone, is a
dated line in /system/updates.log on the card.

Tried on the device: the question, Cancel, and an install of v0.23.0
left unanswered.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0162FokPdvY2KsS4NBfwyWPk

src/services/update_service.h

@@ -51,7 +51,12 @@ class UpdateService : public Service {
     void requestList() { request_ = Request::List; }
     // Downloads `tag` (a release known from the last check or list) into the inactive slot and
     // installs it. "" when it started, or why not.
-    std::string requestInstall(const std::string& tag);
+    // `automatic`: nobody asked for it (issue #52), and the record of updates says so.
+    std::string requestInstall(const std::string& tag, bool automatic = false);
+    // A release the daily check found that may be installed without being asked for (the setting
+    // is on): true once for each find, with its tag. The main loop picks the moment.
+    bool takeOffer(std::string& tag);
+    static constexpr const char* kRecordPath = "/system/updates.log";  // what was installed, and when
     bool giteaBusy() const { return request_ != Request::None || serving_; }
     // Asked to make room for a TLS connection (R1, Q172): IRC steps aside while the Update Service
     // talks to Gitea. Set by the main loop; `true` to step aside, `false` to come back.
@@ -85,6 +90,7 @@ class UpdateService : public Service {
     void listen();
     void install(class UpdateSource& source, const char* via);
     void notify(const std::string& text, NotificationLevel level);
+    void record(const std::string& what);
 
     KeyValueStore& store_;
     WifiService& wifi_;
@@ -103,7 +109,8 @@ class UpdateService : public Service {
     volatile Request request_ = Request::None;
     volatile bool serving_ = false;
     bool held_ = false;  // IRC was asked to step aside, on this task
-    std::string installTag_, fakeVersion_, announced_;
+    std::string installTag_, fakeVersion_, announced_, offered_;
+    volatile bool offer_ = false;
     bool dailyCheck_ = false;
     uint32_t nextCheckMs_ = 90000;  // not before the device has settled
     std::string probeHost_, probePath_;