Fix heap blowout on TBeams (#10155)

* Fix heap blowout on TBeams

* Update src/graphics/draw/MessageRenderer.cpp

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Set MESSAGE_HISTORY_LIMIT to 10 for original ESP32 to optimize RAM usage

* Optimize message frame allocation to prevent excessive memory usage

* Refine message history limits for resource-constrained builds and cap cached lines to prevent heap overflow

* Update src/graphics/draw/MessageRenderer.cpp

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

src/MessageStore.h

@@ -21,8 +21,15 @@
 // How many messages are stored (RAM + flash).
 // Define -DMESSAGE_HISTORY_LIMIT=N in build_flags to control memory usage.
 #ifndef MESSAGE_HISTORY_LIMIT
+#if defined(ARCH_ESP32) &&                                                                                                       \
+    !(defined(CONFIG_IDF_TARGET_ESP32C3) || defined(CONFIG_IDF_TARGET_ESP32S3) || defined(CONFIG_IDF_TARGET_ESP32S2))
+// Baseline ESP32 (non-PSRAM variants) has limited heap; reduce message history on resource-constrained builds.
+// Override with -DMESSAGE_HISTORY_LIMIT=N if needed.
+#define MESSAGE_HISTORY_LIMIT 10
+#else
 #define MESSAGE_HISTORY_LIMIT 20
 #endif
+#endif
 
 // Internal alias used everywhere in code – do NOT redefine elsewhere.
 #define MAX_MESSAGES_SAVED MESSAGE_HISTORY_LIMIT

src/graphics/draw/MessageRenderer.cpp

@@ -422,6 +422,17 @@ void drawTextMessageFrame(OLEDDisplay *display, OLEDDisplayUiState *state, int16
     std::vector<bool> isMine;   // track alignment
     std::vector<bool> isHeader; // track header lines
     std::vector<AckStatus> ackForLine;
+    // Hard limit on total cached lines to prevent unbounded growth from a single long message.
+    // Reserve to the actual cache cap up front, because a single message can expand to many more
+    // wrapped display lines than a small per-message estimate would predict. For a display
+    // rendering only ~5-30 lines at a time, caching more than this limit wastes heap. Stop
+    // appending once we reach MAX_CACHED_LINES to prevent a single message from blowing out the
+    // heap.
+    constexpr size_t MAX_CACHED_LINES = 100U; // ~5-6KB for std::string overhead on 32-bit (if each ~50-60 bytes avg)
+    allLines.reserve(MAX_CACHED_LINES);
+    isMine.reserve(MAX_CACHED_LINES);
+    isHeader.reserve(MAX_CACHED_LINES);
+    ackForLine.reserve(MAX_CACHED_LINES);
 
     for (auto it = filtered.rbegin(); it != filtered.rend(); ++it) {
         const auto &m = *it;
@@ -565,16 +576,23 @@ void drawTextMessageFrame(OLEDDisplay *display, OLEDDisplayUiState *state, int16
 
         int wrapWidth = mine ? rightTextWidth : leftTextWidth;
         std::vector<std::string> wrapped = generateLines(display, "", msgText, wrapWidth);
+        // Per-message wrap-line limit: even if wrapping produces many lines, cap them to prevent
+        // a single long message from consuming most or all of the cache.
+        constexpr size_t MAX_WRAPPED_LINES_PER_MSG = 20U;
+        size_t wrappedCount = 0;
         for (auto &ln : wrapped) {
-            allLines.push_back(ln);
+            if (allLines.size() >= MAX_CACHED_LINES || wrappedCount >= MAX_WRAPPED_LINES_PER_MSG)
+                break; // Cache limit or per-message limit reached; stop adding lines from this message
+            allLines.emplace_back(std::move(ln));
             isMine.push_back(mine);
             isHeader.push_back(false);
             ackForLine.push_back(AckStatus::NONE);
+            ++wrappedCount;
         }
     }
 
     // Cache lines and heights
-    cachedLines = allLines;
+    cachedLines.swap(allLines);
     cachedHeights = calculateLineHeights(cachedLines, emotes, isHeader);
 
     std::vector<MessageBlock> blocks = buildMessageBlocks(isHeader, isMine);