fix: filter editable packages and prune dangling dependency references

[roundhd]

Summary

Monorepo first-party packages with source.editable entries were not filtered by _ignored_package, causing downstream failures when trying to resolve wheels/sdists that don't exist.

After filtering, dependency lists still reference the removed packages, causing further resolution errors.

Changes:

• Add source.editable check to _ignored_package
• After filtering ignored packages, prune dangling references from dependencies and optional-dependencies

Fixes #791
Related: #789

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[aspect-workflows]

Bazel 8 (Test)

All tests were cache hits

31 tests (100.0%) were fully cached saving 48s.

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Bazel 9 (Test)

All tests were cache hits

31 tests (100.0%) were fully cached saving 1m 10s.

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Bazel 8 (Test)

e2e

All tests were cache hits

14 tests (100.0%) were fully cached saving 12s.

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Bazel 9 (Test)

e2e

All tests were cache hits

12 tests (100.0%) were fully cached saving 7s.

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Bazel 8 (Test)

examples/uv_pip_compile

All tests were cache hits

1 test (100.0%) was fully cached saving 335ms.

[arrdem]

Can you elaborate on the use-case here some? I'm not convinced deleting these dependency edges is sound, but I'm open to argument.

In the reworked extension #778, the user is forced to provide a mapping from all editable/virtual firstparty packages to a Bazel target. We no longer delete them. It could be valid for a concrete package to take a dependency on a virtualized/editable vendored copy, in which case this would be incorrect.