feat: enable to ignore cost weights on implementing types

[ysmolski]

This PR adds a feature flag that allows to emulate behavior
of Apollo that ignored weights on implementing types when
the fields on interface does not have cost weight assigned.

It includes the following fixes:

• cost: determine correctly the type of list-wrapped scalars and enums (#1546) (2575480)
• remove connections from transport connection pool (#1541) (ca47200)
• resolve: fix GC-liveness bug in the loadBatchEntityFetch (#1536) (2ad6fc4)

Fixes ENG-9717
Fixes ENG-9779

Summary by CodeRabbit

Summary by CodeRabbit

• New Features
  • Added security.cost_control.ignore_implementing_type_weights (default: false) to ignore @cost weights from implementing types on interface/union fields when the abstract type has no defined weight.
• Tests
  • Added a cost-control test covering the new option, and adjusted related cost-estimation expectations.
• Documentation
  • Updated the configuration schema and full config test data to include the new option.
• Chores
  • Updated the underlying GraphQL tools dependency version.

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Walkthrough

Adds a new IgnoreImplementingTypeWeights boolean flag to the CostControl configuration struct. The flag is wired through the planner builder, JSON schema and test fixtures are updated, graphql-go-tools/v2 is bumped to v2.5.0 in both modules, and integration tests verify the cost header behavior when the flag is enabled.

Changes

IgnoreImplementingTypeWeights Cost Control Feature

Layer / File(s)	Summary
Config field, JSON schema, and test fixture router/pkg/config/config.go, router/pkg/config/config.schema.json, router/pkg/config/testdata/config_full.json	CostControl struct gets IgnoreImplementingTypeWeights bool with YAML/env tags; the JSON schema adds the corresponding ignore_implementing_type_weights boolean under security.cost_control; the full-config fixture includes the new field set to false.
Planner wiring and dependency bump router/core/executor.go, router/go.mod, router-tests/go.mod	buildPlannerConfiguration maps CostControl.IgnoreImplementingTypeWeights to planConfig.IgnoreImplementingTypeWeights; both go.mod files are bumped to graphql-go-tools/v2 v2.5.0.
Integration tests router-tests/security/costs_test.go	New ignore_implementing_type_weights subtest enables the flag in measure mode, runs an interface-implementation query, and asserts that estimated and actual cost headers are lower than without the flag. Existing "nested list with inner object fields" test expectations are updated to reflect new cost calculations.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• wundergraph/cosmo#2913: Touches the same graphql-go-tools/v2 dependency upgrade in both go.mod files.
• wundergraph/cosmo#2925: Also modifies router cost calculation for abstract/interface fields, overlapping in cost-control and header computation areas.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main feature: enabling the ability to ignore cost weights on implementing types, which is the primary objective of this pull request.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

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[github-actions]

Router image scan passed

✅ No security vulnerabilities found in image:

ghcr.io/wundergraph/cosmo/router:sha-7479af4db2ffa588841d70c7cf03213e508e32c2

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.45%. Comparing base (6e4ed19) to head (27769d1).

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #2976       +/-   ##
===========================================
+ Coverage   41.75%   66.45%   +24.70%     
===========================================
  Files         142      258      +116     
  Lines       13755    27558    +13803     
  Branches      711        0      -711     
===========================================
+ Hits         5743    18314    +12571     
+ Misses       8010     7788      -222     
- Partials        2     1456     +1454     

Files with missing lines	Coverage Δ
router/core/executor.go	89.06% <100.00%> (ø)
router/pkg/config/config.go	82.29% <ø> (ø)

... and 398 files with indirect coverage changes

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