Use "Initiate connection" bootloader button label on all Core devices (already on T3W1)

[Hannsek]

Summary

Trezor Safe 7 (T3W1) already shows "Initiate connection" on the bootloader screen, which correctly describes the action of making the device visible to the host. All other Core devices still show the outdated "Install firmware" label, which is misleading since the standard firmware installation path no longer goes through this step.

Use Case

When a user runs trezorctl device reboot-to-bootloader followed by trezorctl device unlock-bootloader, the second command fails with Failed to find a Trezor device. — the user must first tap the button on the bootloader screen to establish the connection, but "Install firmware" gives no indication that this is what the button does.

Expected Behavior

The bootloader screen button is labeled "Initiate connection" consistently across all Core devices, matching the wording already used on T3W1 (Safe 7).

Acceptance Criteria

• "Initiate connection" label applied to T3T1 (Safe 5) bootloader screen
• "Initiate connection" label applied to T3B1 (Safe 3)
• "Initiate connection" label applied to T2T1 (Model T)
• Translation strings updated in Crowdin for all affected models