Extract GobLint.cartesian_*map functions

[sim642]

This is on top of #1886 because I got the idea there.

GobList.cartesian_map unifies two kinds of patterns I found in various places:

1. List.map on BatList.cartesian_product.
2. List.map inside List.concat_map.

In a few places, the variants GobList.cartesian_filter_map and GobList.cartesian_concat_map are introduced.

[Copilot]

Pull request overview

This PR extracts three new utility functions (cartesian_map, cartesian_filter_map, and cartesian_concat_map) into GobList to unify common patterns found throughout the codebase. These patterns typically involved using BatList.cartesian_product followed by List.map, or using List.map inside List.concat_map to achieve cartesian product operations.

Key changes:

• Added three new GobList.cartesian_*map utility functions
• Refactored multiple occurrences of the cartesian product + map pattern across the codebase
• Updated function signatures from tuple-destructuring to separate parameters where appropriate

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/util/std/gobList.ml	Added three new utility functions: cartesian_map, cartesian_filter_map, and cartesian_concat_map
tests/unit/dune	Added -open Goblint_std flag to make GobList functions available
tests/unit/maindomaintest.ml	Replaced BatList.cartesian_product + List.map with GobList.cartesian_map
tests/unit/cdomains/intDomainTest.ml	Removed local cart_op helper and used GobList.cartesian_map
src/domains/intDomainProperties.ml	Replaced cartesian product pattern with GobList.cartesian_map
src/domain/hoareDomain.ml	Multiple conversions to GobList.cartesian_map and cartesian_filter_map
src/cdomains/congruenceClosure.ml	Removed local map2 helper, converted to GobList.cartesian_map, added TODO for potential future extraction
src/cdomain/value/cdomains/structDomain.ml	Kept BatList.cartesian_product with TODO comments for potential future conversion
src/cdomain/value/cdomains/int/intervalSetDomain.ml	Converted multiple functions to use all three cartesian variants, updated function signatures from tuple to separate parameters
src/arg/myARG.ml	Renamed cartesian_concat_paths to cartesian_append and implemented with GobList.cartesian_map
src/analyses/extractPthread.ml	Updated lambda signature and used GobList.cartesian_map

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