build: update Fortio and libneo pins

[krystophny]

Pin direct Fortio use to 829fcde, the validated continuation-reader and bulk complex-writer fix, and move the default libneo dependency to 95f5c87 so its complete Fortio rollout is used.

[krystophny]

Dependency follow-up: this branch now pins libneo bridge 9f1e9dcf5ab6800213415eac485e85a6d395f72a from libneo PR itpplasma/libneo#413, which consumes standalone Fortio 11afd0bd1af0c99ea4e9a1c0df683dbdcc299b69 from Fortio PR lazy-fortran/fortio#68. No system HDF5 link is introduced.

[krystophny]

Correction: the compatible main-line libneo bridge is PR itpplasma/libneo#414 at commit 7262c32bf0406594a8ef27e84654d249aef2cb86. This replaces the FortFEM-specific bridge reference; it consumes standalone Fortio PR lazy-fortran/fortio#68. The consumer branch has been updated and CI restarted.

[GeorgGrassler]

@krystophny I assume this change is not necessary anymore once the current (already pin updated) #118 lands?

[krystophny]

Closing as superseded by #118. That PR contains the same Fortio and libneo pin updates together with the direct candidate-gate work, and its checks are green.