feat: 5 improvements — file info, download verify, UART warning, status display, COM port reuse

- file_utils: compute_file_info() — CRC32, human-readable size, mtime
- StatusDisplay: simplified to info-only key-value panel; status messages
  removed (log-only); file info shown in status panel at startup/select
- config: added download_verify checkbox (default ON), skips Step 4.2
- UART warning: CTkTextbox with word-wrap and auto-height
- COM port: check_uart_available / test_serial_version accept optional
  UartMonitor to avoid redundant serial opens (Error 13 on Windows)
- layout: left:right 7:3 ratio, config panel stretches full width

src/config_manager.py

@@ -28,13 +28,14 @@ DEFAULT_CONFIG: dict[str, Any] = {
     "flash_type": "qspi-x4-single",
     "flash_model": "s25fl256s1",
     "erase_all": False,
+    "download_verify": True,
     "firmware_bin_path": "",
     "reboot_timeout": 30,
     "ping_timeout": 5,
     "ping_count": 3,
     "uart_delay": 3,
     "inter_step_delay": 2,
-    "boot_wait_delay": 10,
+    "boot_wait_delay": 30,
     "step_timeouts": {
         "check_env": 120,
         "flash_erase": 120,
@@ -67,6 +68,7 @@ class Config:
     flash_type: str = "qspi-x4-single"
     flash_model: str = "s25fl256s1"
     erase_all: bool = False
+    download_verify: bool = True
     firmware_bin_path: str = ""
     reboot_timeout: int = 30
     ping_timeout: int = 5
@@ -176,6 +178,7 @@ class Config:
             "flash_type": self.flash_type,
             "flash_model": self.flash_model,
             "erase_all": self.erase_all,
+            "download_verify": self.download_verify,
             "firmware_bin_path": self._relative_path(self.firmware_bin_path),
             "reboot_timeout": self.reboot_timeout,
             "ping_timeout": self.ping_timeout,