feat: silent-restart defrag on section-build double failure + BLE debug flags

- EpubReaderActivity: when a section build fails even after the BLE
  teardown/retry, silentRestartToReader() as last-resort heap defrag,
  guarded by bootWasSilentRestart() to prevent reboot loops
- main/SilentRestart.h: expose bootWasSilentRestart()
- platformio.ini: enable FREEINK_BLE_HID_REPORT_DEBUG in env:default

src/SilentRestart.h

@@ -6,3 +6,7 @@
 
 void silentRestart();          // home screen
 void silentRestartToReader();  // currently-open EPUB (APP_STATE.openEpubPath)
+// True when this boot itself came from a silent restart. Callers that restart
+// as a last-resort defrag must check this so a failure that survives the
+// restart degrades to an error instead of a reboot loop.
+bool bootWasSilentRestart();

src/activities/reader/EpubReaderActivity.cpp

@@ -33,6 +33,7 @@
 #include "QrDisplayActivity.h"
 #include "ReaderUtils.h"
 #include "RecentBooksStore.h"
+#include "SilentRestart.h"
 #include "components/UITheme.h"
 #include "fontIds.h"
 #include "util/BookmarkUtil.h"
@@ -883,6 +884,16 @@ void EpubReaderActivity::render(RenderLock&& lock) {
         bleinput::showConnectingUntilLinked(renderer, mappedInput);
         requestGhostCleanup();
       }
+      if (!built && !bootWasSilentRestart()) {
+        // Even with BLE freed, the build can fail when this session's parse churn has
+        // fragmented the heap beyond in-place recovery. A silent restart is the only
+        // real defrag on this heap (no compaction); it resumes into this book and
+        // rebuilds the section on a fresh heap. Guarded by bootWasSilentRestart() so a
+        // build that fails again after the restart degrades to the error popup below
+        // instead of reboot-looping.
+        LOG_ERR("ERS", "Section build failed after BLE recovery; silent restart to defrag heap");
+        silentRestartToReader();
+      }
       if (!built) {
         LOG_ERR("ERS", "Failed to persist page data to SD");
         section.reset();

src/main.cpp

@@ -128,6 +128,12 @@ enum class BootResume : uint8_t {
   QuickResume,  // wake from a quick-resume deep sleep (SD flag; survives power loss)
 };
 
+// Latched in setup() from the read-and-clear of the RTC flag, so the reboot-loop
+// guard in bootWasSilentRestart() has the answer for the whole session.
+static bool bootWasSilentRestartFlag = false;
+
+bool bootWasSilentRestart() { return bootWasSilentRestartFlag; }
+
 // Latched true once enterDeepSleep() commits to sleeping, before it tears down
 // the current activity. WiFi activities call silentRestart() in onExit() to
 // clear heap fragmentation on the way out, but deep sleep is a full chip reset
@@ -330,6 +336,7 @@ void setup() {
       (isSilentReboot && silentRebootTarget <= SILENT_REBOOT_TARGET_READER) ? silentRebootTarget : 0;
   silentRebootMagic = 0;
   silentRebootTarget = 0;
+  bootWasSilentRestartFlag = isSilentReboot;
 
   gpio.begin();
   powerManager.begin();