The SD page cache (16af3b5) made the SD card a soft dependency of
NomadNet page loads, but its step machine retries a transient storage
result (BUSY = SPI-mutex timeout, UNAVAILABLE = card not mounted)
forever with no budget. On a persistently unhealthy seam the boot-time
recovery pins operation_ != NONE, the flow stays LOOKUP, and the UI
freezes at 'Checking SD page cache...' (the CACHE state has no
deadline, unlike every other NomadNet state).
NomadNetCache::service() now compares each call's entry state to the
previous call's. Any advance (op, offset, scan/cleanup index, scan
count, open-flags) resets a stall counter, so slow-but-progressing
steps (chunked 64 KB transfers, up to 96-record directory scans) never
false-trip; a no-progress tick is a transient stall. Past 500
consecutive no-progress ticks (far beyond any real SPI contention or
SD mount window) the cache bails: mark the namespace non-authoritative
for the session (lookups/commits bypass) and clear the op, so the flow
falls through to a live fetch -- the pre-cache page-load behavior.
Regression tests: cache-level (persistent UNAVAILABLE recovery bails;
lookup bypasses after bail) and flow-level (a permanently BUSY
beginList no longer parks the flow in LOOKUP; it reaches NEED_LIVE in
bounded ticks). Both fail on the pre-fix code and pass with it.
Verified: tdeck firmware build SUCCESS; tests/native 121 passed (3
pre-existing env failures, fail identically on origin/main baseline);
tests/build_scripts 184 passed.
Torlando