[arthurscchan]

This PR adds a new OSS-Fuzz fuzzerwith corpus/dict targets tree exec, together with google/oss-fuzz#16434 to enable a new fuzzer for project behaviortreecpp.

[facontidavide]

Thanks @arthurscchan, this is the most useful of the three: until now nothing in OSS-Fuzz ticked a tree.

I pushed one commit (ee9832f) on top of a merge of master. It removes the references to files that aren't in this repository (findings/bt_tree_exec_fuzzer/README.md, "btcpp-1", the coverage-pipeline report) and the unused wakeup_aware variable, and flattens the nested anonymous namespace. The generated trees and the consumed bytes are unchanged. It builds with clang-21 and ran clean for 60 s on the seed corpus (about 915 exec/s).

The ~Tree() abort you worked around is real, and I reproduced it on master: #1281. Once that's fixed we can generate catch_on_halt="true" again. I'll squash-merge this once CI is green.

Heads-up: #1277, #1278 and #1279 all edit the same line of cmake/fuzzing_build.cmake, so the other two will need a rebase.