Forward-port of #10754 and #10757 from master (2.7) into develop, so the
develop->master 2.8 promotion (#10777) doesn't drop them.
#10754: PhoneAPI no longer walks the filesystem to build the file manifest on
node-info-only config requests (SPECIAL_NONCE_ONLY_NODES), which never consume
it. getFiles() is now bounded (default 64 entries, depth 3) via collectFiles(),
takes an optional wasLimited out-param, and reserves capacity with a bad_alloc/
length_error fallback. The manifest vector is freed via swap (releaseFilesManifest).
#10757: getFiles()/collectFiles() now guard against empty file names returned by
the Adafruit LittleFS nRF52 glue (issue 4395).
Ported by hand rather than cherry-picked: master had reflowed FSCommon.cpp to a
different brace style (every line conflicted), #10754 already subsumes #10757,
and develop carries a MESHTASTIC_EXCLUDE_FILES_MANIFEST path (nRF54L15) that
master lacks. The exclude path is preserved and now also short-circuits + frees
the manifest. Verified: native Docker suite 448/448, clang-format clean.
Ben MeadorsandGitHub
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