msc: arm mass-storage magic on confirm, and flush the log before reset

[erichelgeson]

Resolves issue on wide/sca rebooting into msc.

[github-actions]

Test this PR

Flash the firmware built from 90e8824: BlueSCSI binaries.zip

• see Updating Firmware for how to flash it.

_{Must be signed in to GitHub. Build expires after 90 days.}

BlueSCSI Memory Report

Compared against release v2026.08.17

Memory Usage

Target	FLASH	RAM	SCRATCH_X	SCRATCH_Y
Pico_2_Audio_SPDIF	687.1 KB (+1.5 KB) [34%]	511.7 KB [100%]	3.5 KB [88%]	3.8 KB [94%]
Pico_2_DaynaPORT	679.4 KB (+1.5 KB) [33%]	511.7 KB [100%]	3.5 KB [88%]	3.0 KB [75%]
Pico_Audio_SPDIF	710.1 KB (+1.6 KB) [35%]	252.6 KB [99%]	1.5 KB [38%]	768 B [19%]
Pico_DaynaPORT	701.9 KB (+1.6 KB) [34%]	246.3 KB [96%]	1.5 KB [38%]	—
Ultra	696.8 KB (+1.5 KB) [34%]	511.7 KB [100%]	3.5 KB [88%]	3.0 KB [75%]
Ultra_Wide	455.3 KB (+1.2 KB) [22%]	511.7 KB [100%]	2.0 KB [50%]	3.0 KB [75%]

Symbol Region Changes

Pico_Audio_SPDIF: 4 symbols moved RAM → FLASH (-312 B RAM)

Symbol	Size
void logmsg<char const*, char const*>(char const*, char const*)	80 B
void logmsg<char const*, char*>(char const*, char*)	80 B
void logmsg<char const*, unsigned long>(char const*, unsigned long)	80 B
void logmsg<char const*>(char const*)	72 B

Pico_DaynaPORT: 4 symbols moved RAM → FLASH (-312 B RAM)

Symbol	Size
void logmsg<char const*, char const*>(char const*, char const*)	80 B
void logmsg<char const*, char*>(char const*, char*)	80 B
void logmsg<char const*, unsigned long>(char const*, unsigned long)	80 B
void logmsg<char const*>(char const*)	72 B