[logger] Inline ANSI reset sequence in LogBuffer::finalize_()

Replace write_() call with direct char stores for the 4-byte
ANSI reset sequence ("\033[0m"). This eliminates function call
overhead (entry/retw, bounds check, memcpy setup) on every log
message and avoids a rodata string reference that consumes RAM
on ESP8266.

esphome/components/logger/log_buffer.h

@@ -128,12 +128,21 @@ struct LogBuffer {
     }
   }
   void finalize_() {
-    // Write color reset sequence
-    static constexpr uint16_t RESET_COLOR_LEN = sizeof(ESPHOME_LOG_RESET_COLOR) - 1;
-    this->write_(ESPHOME_LOG_RESET_COLOR, RESET_COLOR_LEN);
+    this->write_ansi_reset_();
     // Null terminate
     this->data[this->full_() ? this->size - 1 : this->pos] = '\0';
   }
+  // Write ANSI reset sequence inline (4 bytes: "\033[0m") - avoids write_() call overhead
+  void write_ansi_reset_() {
+    if (this->remaining_() >= 4) {
+      char *p = this->current_();
+      *p++ = '\033';
+      *p++ = '[';
+      *p++ = '0';
+      *p++ = 'm';
+      this->pos += 4;
+    }
+  }
   void strip_trailing_newlines_() {
     while (this->pos > 0 && this->data[this->pos - 1] == '\n')
       this->pos--;