The common-config.nix sets PREEMPT_LAZY = yes for kernels >= 6.18
(which includes 7.1). Both PREEMPT and PREEMPT_LAZY are in the same
preemption model choice group in kernel Kconfig. When generate-config.pl
sees both options with 'y' in the answer file, it dies with
'conflicting answers!' (the "Error in reading or end of file" failure).

Explicitly disabling PREEMPT_LAZY ensures only PREEMPT (full preemption)
is selected, avoiding the choice conflict. Also removes CC_IS_CLANG and
LTO_CLANG_FULL which can't be forced via kernel config with GCC build.

These options can't be forced via kernel config — CC_IS_CLANG is a
def_bool auto-detected from --version, and LTO_CLANG_FULL
requires the clang compiler (the build uses GCC from default stdenv).

When generate-config.pl tries to answer 'y' for these options with the
GCC toolchain, make config rejects the answer, the question-answering
loop diverges, and the builder exits 255 with 'Error in reading or end
of file' repeated in the log.

Also bumps kernel from linux_7_0 to linux_7_1.

Module-CPANTS-Analyse 1.02 test t/analyse/manifest.t creates a symlink
with an absolute target. Archive::Any::Lite 0.11 refuses to extract it
under SECURE EXTRACT MODE, causing the test to fail.

This cascades: Test-Kwalitee → Finance-Quote → gnucash breaks.

Previous attempt used perl5.override { overrides = ... } which does a
shallow // merge — it doesn't propagate to internal fixpoint references
inside makeScopeWithSplicing'. Test-Kwalitee was still pulling the
original ModuleCPANTSAnalyse (with tests enabled).

Now uses overrideScope on the perl package set itself, which rebuilds
the entire scope fixpoint. All packages that depend on ModuleCPANTSAnalyse
(Test-Kwalitee, Finance-Quote, etc.) get the overridden version.

Also remove stale submodule entries from piBTW/.gitmodules
(pi-subagents, pi-intercom) that caused nix flake update to fail.