Fix memory overflow in getFiles() causing device crashes

[capricornusx]

• Replace recursive vector allocation with reference passing in getFiles()
• Add heap memory check before file manifest generation in PhoneAPI
• Limit file count to 50 to prevent memory exhaustion
• Add safety checks for file paths and names
• Include unit tests for memory protection logic

Fixes crash when Android app connects to web server due to std::bad_alloc in getFiles() function during file manifest generation.

Serial log output

INFO | 18:50:21 476 [ServerAPI] Client wants config, nonce=11

abort() was called at PC 0x401febbf on core 1
#0 0x401febbf in __cxxabiv1::__terminate(void (*)()) at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:47

Backtrace: 0x4008414d:0x3ffd7db0 0x400976fd:0x3ffd7dd0 0x4009d531:0x3ffd7df0 0x401febbf:0x3ffd7e70 0x401fec06:0x3ffd7e90 0x401fef4b:0x3ffd7eb0 0x401feeaa:0x3ffd7ed0 0x4015a141:0x3ffd7ef0 0x40159f56:0x3ffd8050 0x401388b2:0x3ffd81b0 0x4012e5c9:0x3ffd8400 0x40139fd3:0x3ffd8420 0x4013f451:0x3ffd8440 0x40150de6:0x3ffd8460 0x4013bed9:0x3ffd8480 0x400e9545:0x3ffd84d0
#0 0x4008414d in panic_abort at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/esp_system/panic.c:408
#1 0x400976fd in esp_system_abort at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/esp_system/esp_system.c:137
#2 0x4009d531 in abort at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/newlib/abort.c:46
#3 0x401febbf in __cxxabiv1::__terminate(void ()()) at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:47
#4 0x401fec06 in std::terminate() at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:57
#5 0x401fef4b in __cxa_throw at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/gcc/libstdc++-v3/libsupc++/eh_throw.cc:95
#6 0x401feeaa in operator new(unsigned int) at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/gcc/libstdc++-v3/libsupc++/new_op.cc:54
#7 0x4015a141 in getFiles(char const, unsigned char) at ??:?
#8 0x40159f56 in getFiles(char const*, unsigned char) at ??:?
#9 0x401388b2 in PhoneAPI::handleToRadio(unsigned char const*, unsigned int) at ??:?
#10 0x4012e5c9 in StreamAPI::runOncePart() at ??:?
#11 0x40139fd3 in ServerAPI<WiFiClient>::runOnce() at :?
#12 0x4013f451 in non-virtual thunk to ServerAPI<WiFiClient>::runOnce() at :?
#13 0x40150de6 in concurrency::OSThread::run() at ??:?
#14 0x4013bed9 in loop() at ??:?
#15 0x400e9545 in loopTask(void*) at :?

ELF file SHA256: 135cc040bef33510

E (12115) esp_core_dump_flash: Core dump flash config is corrupted! CRC=0x7bd5c66f instead of 0x0
Rebooting...

🤝 Attestations

• I have tested that my proposed changes behave as described.
• I have tested that my proposed changes do not cause any obvious regressions on the following devices:
  • TLORA_V2_1_16

[Copilot]

Pull Request Overview

This PR fixes a critical memory overflow issue in the getFiles() function that was causing Android app crashes due to std::bad_alloc exceptions during file manifest generation. The fix implements memory protection mechanisms and limits file enumeration to prevent device crashes.

Key changes:

• Replaces recursive vector allocation with reference passing in getFiles()
• Adds heap memory checks before file manifest generation
• Implements a 50-file limit to prevent memory exhaustion

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/FSCommon.cpp	Refactors getFiles() to use reference passing and adds safety checks for file paths and count limits
src/mesh/PhoneAPI.cpp	Adds heap memory validation before file manifest generation to prevent crashes
test_memory_fix/test/test_memory/test_main.cpp	Adds unit tests for memory protection logic and file counting limits
test_memory_fix/platformio.ini	Configures test environment for memory protection unit tests

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[capricornusx]

@thebentern
Is anything else needed from me before merging?

[capricornusx]

@thebentern, please, re-run job

[capricornusx]

up