Cardano Updates

PostgreSQL's JIT support pulls in LLVM 20, which OOMs during musl
cross-compilation (SLPVectorizer.cpp requires 4-8 GB RAM per thread).
JIT is unnecessary for static build environments, so disabling it
removes the LLVM dependency entirely.

This fixes the 28 *-static-iog-full-* build failures across
aarch64-linux and x86_64-linux platforms (eval 372).

Two root cause fixes for the 92 cascading build failures in eval 370:

1. OpenSSL musl cross-build (48 aarch64-linux static failures):
   Skip the flaky 82-test_ocsp_cert_chain.t test which fails in the nix
   sandbox. Only 1 of 3888 tests fails, testing OCSP stapling which
   requires network conditions unavailable in sandboxed cross-compilation.

2. happy-2.1.7 disallowedRequisites (8 aarch64-darwin minimal-ghc failures):
   nixpkgs-2511 enables disallowGhcReference=true in justStaticExecutables.
   The happy binary transitively references GHC through happy-lib, and
   postFixup's rm -rf $out/lib cannot break this reference chain since
   happy-lib lives in the Nix store. Override to disable the check.

This reverts commit c93bf69cf7bea3232673c56f2c301f5302961785.

Flake lock file updates:

• Updated input 'cabal':
    'github:stable-haskell/cabal/c0d52b2' (2025-03-30)
  → 'github:stable-haskell/cabal/0a74ea1' (2025-07-28)
• Updated input 'cabal-experimental':
    'github:stable-haskell/cabal/7e50837' (2025-04-07)
  → 'github:stable-haskell/cabal/7ea381f' (2025-05-22)
• Updated input 'haskellNix':
    'github:input-output-hk/haskell.nix/835d1d8' (2025-04-04)
  → 'github:input-output-hk/haskell.nix/962394c' (2026-02-07)
• Removed input 'haskellNix/ghc-8.6.5-iohk'
• Updated input 'haskellNix/hackage':
    'github:input-output-hk/hackage.nix/9f3c25c' (2025-04-04)
  → 'github:input-output-hk/hackage.nix/5e6caa6' (2026-02-07)
• Updated input 'haskellNix/hackage-for-stackage':
    'github:input-output-hk/hackage.nix/fdd3d2b' (2025-04-04)
  → 'github:input-output-hk/hackage.nix/5fcc92e' (2026-02-07)
• Added input 'haskellNix/hackage-internal':
    'github:input-output-hk/hackage.nix/f7867ba' (2025-06-19)
• Added input 'haskellNix/hls-2.11':
    'github:haskell/haskell-language-server/46ef452' (2025-05-15)
• Added input 'haskellNix/hls-2.12':
    'github:haskell/haskell-language-server/7d983de' (2025-09-24)
• Updated input 'haskellNix/iserv-proxy':
    'github:stable-haskell/iserv-proxy/e9dc86e' (2025-03-16)
  → 'github:stable-haskell/iserv-proxy/91ef7ff' (2026-02-04)
• Updated input 'haskellNix/nixpkgs-2411':
    'github:NixOS/nixpkgs/94792ab' (2025-02-10)
  → 'github:NixOS/nixpkgs/5ab036a' (2025-06-30)
• Added input 'haskellNix/nixpkgs-2505':
    'github:NixOS/nixpkgs/6c8f0cc' (2025-12-01)
• Added input 'haskellNix/nixpkgs-2511':
    'github:NixOS/nixpkgs/b0924ea' (2025-12-01)
• Updated input 'haskellNix/nixpkgs-unstable':
    'github:NixOS/nixpkgs/041c867' (2025-01-17)
  → 'github:NixOS/nixpkgs/c1cb7d0' (2025-12-01)
• Updated input 'haskellNix/stackage':
    'github:input-output-hk/stackage.nix/b7d2fd6' (2025-04-04)
  → 'github:input-output-hk/stackage.nix/9d52557' (2026-02-07)
• Updated input 'iohk-nix':
    'github:input-output-hk/iohk-nix/3acad18' (2025-04-03)
  → 'github:input-output-hk/iohk-nix/0ce7cc2' (2026-02-02)
• Updated input 'iohk-nix/nixpkgs':
    'github:nixos/nixpkgs/55af203' (2023-05-15)
  → 'github:nixos/nixpkgs/a47938d' (2025-06-28)

Some shell variants (static, js) have nested lists in their
nativeBuildInputs. Use lib.flatten to handle this before
passing to lib.makeBinPath.