build: update MSRV to nightly-2025-12-11

[DemesneGH]

Changes:

• Updated setup_std_dependencies.sh to clone the pinned Rust source and apply patches from teaclave-crates trustzone-sdk: add ported std and libc for OP-TEE std TAs teaclave-crates#10. After that PR merged the clone source should be updated in setup_std_dependencies.sh.
• Resolved compilation and Clippy errors introduced by the newer compiler version.
• Continued use of Xargo for this transition, with XARGO_RUST_SRC pointing to the new library/ workspace.

Status:

• Basic CI passes.
• Temporarily excluded std-for-dev-docker and cargo-optee-* for this PR. Since the build toolchain will be overhauled in the next step, these environments will be updated accordingly at that time.

Next Steps:

• Migrate from Xargo to cargo -Z build-std as the primary build tool, as Xargo is outdated and no longer updated.
• Fix remaining CI errors in the excluded components.

[ivila]

There are duplicate files in the cargo-optee directory. Should these be updated as well, or would it be better to remove them entirely?

[DemesneGH]

The modification of cargo-optee is planned in the follow-up PRs, after this PR merged I will remove the Xargo and update our building system. To reduce the effort of multiple modifications I plan to adjust the cargo-optee after that.
For this PR, I suggest we omit the CI errors of cargo-optee and std-dev-docker.

[ivila]

cargo-optee adds the build-std flag by default; I think we should remove that as well.

teaclave-trustzone-sdk/cargo-optee/src/ta_builder.rs

Lines 362 to 368 in 925a5d4

	// Add no-std specific flags to avoid the linking error of _Unwind_Resume
	if !config.std {
	cmd.arg("-Z").arg("build-std=core,alloc");
	cmd.arg("-Z")
	.arg("build-std-features=panic_immediate_abort");
	}

[DemesneGH]

Reorganized the commits, will merge this PR later if there're no follow-up comments today, thanks!