feat: Improve the firmware screen

[mondalaci]

Summary

Implements the firmware-screen improvements described in #2593:

• Per-device progress bars with live percentage. Each device row (dongle, keyboard halves, modules) shows a thin 5px determinate progress bar with a percentage while it's being flashed. Real progress is wired from the mcumgr image upload and kboot write-memory operations up through a new moduleFirmwareUpgradeProgress IPC event and stored per-module.
• Noticeable USB-cable warning. The "connect the left/right half via USB" prompt is now surfaced as a prominent warning banner on the firmware screen via a dedicated firmwareUpgradeConnectPrompt IPC signal, rather than being buried in the update log. It shows only while a cable action is required and clears automatically once the half is connected.
• Toggleable update log. The firmware update log is hidden by default. A Show update log / Hide update log link appears from the moment the log has any text.

Implementation notes

• Progress callbacks were threaded through mcumgr.imageUpload, kboot.writeMemory (+ peripheral), and the uhk-operations flash methods; device.service reports throttled integer percentages keyed by module name.
• New uhk-common models: ModuleFirmwareUpgradeProgress, FirmwareUpgradeConnectPrompt.
• Store: new actions, reducer state (progressPercent per module, connectPrompt), and selector output; renderer service listens for the new IPC events.
• Progress bar width roughly reflects the device line width; spacing below the last device entry keeps the bars clear of the flash buttons.

Test plan

• UHK 60 (KBOOT): flash firmware and confirm per-module progress bars advance with percentages.
• UHK 80 (MCUBOOT): flash firmware and confirm right-half, left-half, and dongle progress bars advance.
• UHK 80: trigger the left/right cable step and confirm the warning banner appears and clears on reconnect.
• Confirm the update log is hidden by default and the Show/Hide link appears once logging starts and toggles the log.

Closes #2593

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