In sha256 metadata calculation PR, python tooling error

[PThierry]

when updating metadatas fior userspace applications by including sha256 value, the python tooling fails due to schema incompatibility.

Linked to #116

[19/23] generate task calculator-app metadata
genmetadata: ../../src/kernel/subprojects/nlohmann_json-3.12.0/single_include/nlohmann/json.hpp:22188: const nlohmann::json_abi_v3_12_0::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType, CustomBaseClass>::value_type& nlohmann::json_abi_v3_12_0::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType, CustomBaseClass>::operator[](const typename object_t::key_type&) const [with ObjectType = std::map; ArrayType = std::vector; StringType = std::__cxx11::basic_string<char>; BooleanType = bool; NumberIntegerType = long int; NumberUnsignedType = long unsigned int; NumberFloatType = double; AllocatorType = std::allocator; JSONSerializer = nlohmann::json_abi_v3_12_0::adl_serializer; BinaryType = std::vector<unsigned char>; CustomBaseClass = void; const_reference = const nlohmann::json_abi_v3_12_0::basic_json<>&; typename object_t::key_type = std::__cxx11::basic_string<char>; object_t = std::map<std::__cxx11::basic_string<char>, nlohmann::json_abi_v3_12_0::basic_json<>, std::less<void>, std::allocator<std::pair<const std::__cxx11::basic_string<char>, nlohmann::json_abi_v3_12_0::basic_json<> > > >]: Assertion `it != m_data.m_value.object->end()' failed.
[11:00:13] CRITICAL Command '['/home/phil/Camelot/projects/calculator/output/staging/usr/local/bin/genmetadata', '-o', '/home/phil/Camelot/projects/calculator/output/build/camelot_private/calculator-app.meta',             barbican.py:122
                    '{"task_meta": {"heap_size": 0, "label": 3221352450, "priority": 2, "quantum": 2, "stack_size": 296, "capabilities": ["dev_buses", "dev_io"], "devs": [12], "version": 1, "magic": 3735931646, "flags":                  
                    ["auto_start", "exit_norestart"], "s_text": 134270976, "text_size": 10412, "s_got": 536903808, "got_size": 0, "s_svcexchange": 536903680, "data_size": 20, "bss_size": 944, "entrypoint_offset": 1,                      
                    "domain": 0, "rodata_size": 0, "finalize_offset": 0, "num_devs": 1, "shms": [], "num_shms": 0, "dmas": [], "num_dmas": 0, "task_hmac": [], "metadata_hmac": []}}']' died with <Signals.SIGABRT: 6>.                      
Traceback (most recent call last):
  File "/home/phil/.venv/bin/barbican", line 6, in <module>
    sys.exit(main())
             ~~~~^^
  File "/home/phil/.venv/lib/python3.13/site-packages/camelot/barbican/barbican.py", line 117, in main
    run_internal_command(sys.argv[2], sys.argv[3:])
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/phil/.venv/lib/python3.13/site-packages/camelot/barbican/barbican.py", line 97, in run_internal_command
    module.run(argv)
    ~~~~~~~~~~^^^^^^
  File "/home/phil/.venv/lib/python3.13/site-packages/camelot/barbican/_internals/gen_task_metadata_bin.py", line 109, in run
    run_gen_task_metadata_bin(
    ~~~~~~~~~~~~~~~~~~~~~~~~~^
        args.input, args.output, ProjectPath.load(args.projectdir / "output" / "build")
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/home/phil/.venv/lib/python3.13/site-packages/camelot/barbican/_internals/gen_task_metadata_bin.py", line 84, in run_gen_task_metadata_bin
    _gen_metadata(output, {"task_meta": task_metadata}, path)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/phil/.venv/lib/python3.13/site-packages/camelot/barbican/_internals/gen_task_metadata_bin.py", line 29, in _gen_metadata
    subprocess.run(cmdline, check=True)
    ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/subprocess.py", line 577, in run
    raise CalledProcessError(retcode, process.args,
                             output=stdout, stderr=stderr)
subprocess.CalledProcessError: Command '['/home/phil/Camelot/projects/calculator/output/staging/usr/local/bin/genmetadata', '-o', '/home/phil/Camelot/projects/calculator/output/build/camelot_private/calculator-app.meta', '{"task_meta": {"heap_size": 0, "label": 3221352450, "priority": 2, "quantum": 2, "stack_size": 296, "capabilities": ["dev_buses", "dev_io"], "devs": [12], "version": 1, "magic": 3735931646, "flags": ["auto_start", "exit_norestart"], "s_text": 134270976, "text_size": 10412, "s_got": 536903808, "got_size": 0, "s_svcexchange": 536903680, "data_size": 20, "bss_size": 944, "entrypoint_offset": 1, "domain": 0, "rodata_size": 0, "finalize_offset": 0, "num_devs": 1, "shms": [], "num_shms": 0, "dmas": [], "num_dmas": 0, "task_hmac": [], "metadata_hmac": []}}']' died with <Signals.SIGABRT: 6>.