fix(sync-service): array cast assigns element type instead of array type

[robacourt]

Summary

• Where clauses like "organization_ids" @> ARRAY[$1]::uuid[] return HTTP 400 (Could not select an operator overload) whenever the inner ARRAY[...] constructor contains a non-foldable element (a column ref, or a parameter inside a sub-expression that the parser can't reduce ahead of the outer cast).
• Root cause is in Electric.Replication.Eval.Parser.as_dynamic_cast/3: the :array_cast branch built a Func with type: extract_base_type_name(target_type) plus map_over_array_in_pos: 0. So for target {:array, :uuid} it stored .type = :uuid while the runtime value is still an array — and the operator-overload lookup (Lookups.pick_concrete_operator_overload/3) reads .type literally, can't match anyarray @> anyarray, and the API surfaces a 400. cast_implicit/3 and the ANY/ALL builder set the same misleading scalar type, and try_applying/1 had a wrap-in-{:array, _} kludge at line 1582 to paper over it.

This PR changes the convention so Func.type always reflects the runtime type of the value the Func produces:

• as_dynamic_cast/3 :array_cast branch now keeps the full target array type.
• cast_implicit/3 array branch now stores {:array, to_type}.
• handle_any_or_all/2's bool_array now stores {:array, :bool}.
• try_applying/1 drops the conditional wrap.

The bug stayed hidden for the all-constant case because do_maybe_reduce/1 folds ARRAY[Const, ...] into a Const{type: {:array, T}, value: [...]} before the outer cast runs; the parser test added in this PR uses a column ref to keep the Array unreduced and exposes the mis-typed Func directly.

Test plan

• mix test packages/sync-service/test/electric/replication/eval/parser_test.exs — 85 tests, including the new minimal assertion at parser_test.exs:1092
• mix test packages/sync-service/test/electric/replication/eval/ — 227 tests + 6 properties + 3 doctests, 0 failures
• mix test packages/sync-service/test/electric/shapes/filter_test.exs — 135 tests, 0 failures (covers array_field @> const_array inclusion-index optimisation)
• mix test packages/sync-service/test/electric/shapes/querying_test.exs — 28 tests, 0 failures
• CI green

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.99%. Comparing base (ed48bba) to head (fcbd798).
⚠️ Report is 3 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4348      +/-   ##
==========================================
- Coverage   59.19%   58.99%   -0.20%     
==========================================
  Files         305      290      -15     
  Lines       28415    27871     -544     
  Branches     7495     7496       +1     
==========================================
- Hits        16819    16442     -377     
+ Misses      11582    11415     -167     
  Partials       14       14              

Flag	Coverage Δ
electric-telemetry	?
elixir	?
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packages/agents-mcp	77.54% <ø> (ø)
packages/agents-runtime	80.03% <ø> (+0.06%)	⬆️
packages/agents-server	73.15% <ø> (-0.31%)	⬇️
packages/agents-server-ui	6.04% <ø> (ø)
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[alco]

👍

[github-actions]

This PR has been released! 🚀

The following packages include changes from this PR:

• @core/sync-service@1.6.6

Thanks for contributing to Electric!