SD card boot loop / load crash fix: increase watchdog and SD init timeout

[Akku-21]

Problem

When using certain SD cards (tested with Samsung 16GB HC Class 10), the Performer either:

1. Boot loops — the progress bar fills and the board resets repeatedly
2. Crashes when loading a project — works fine without SD card, but crashes when trying to load a saved project

Root Cause

Two timeouts are too short for high-capacity SD cards that take longer to initialize in SPI compatibility mode:

1. Watchdog timeout in src/apps/sequencer/Sequencer.cpp is set to 1000ms, which is too short for the SD card init sequence on some cards
2. ACMD41 timeout in src/platform/stm32/drivers/SdCard.cpp is set to 2000ms, which is insufficient for some SDHC cards

Related issue: #368 describes the same CMD8/ACMD41 timeout problem.

Fix

src/apps/sequencer/Sequencer.cpp line 153:

// Before
System::startWatchdog(1000);

// After
System::startWatchdog(5000);

src/platform/stm32/drivers/SdCard.cpp line 225:

// Before
uint32_t timeout = os::ticks() + os::time::ms(2000);

// After
uint32_t timeout = os::ticks() + os::time::ms(4000);

Result

After applying both changes, the following SD cards work correctly:

• ✅ Samsung 16GB HC Class 10 (previously failing)
• ✅ SanDisk 8GB (was already working)

Tested on a DIY build with firmware v0.1.42.