Use oxc resolver for import graph resolution

[longlho]

Summary

• Replace the hand-rolled relative import resolver with a narrow oxc_resolver adapter
• Follow project files resolved through tsconfig paths, package imports, Node-style extension aliases, and package exports while keeping external deps outside Codescythe’s graph
• Add a shared oxc-resolution fixture that doubles as an example for resolver behavior
• Add analyzer unit coverage and a Bazel CLI e2e test that runs the compiled codescythe binary against the fixture
• Use REPO.bazel ignore_directories for the local .worktrees scratch directory instead of .bazelignore

Validation

• cargo fmt --check
• cargo test -p codescythe
• cargo test -p codescythe_cli
• bazel test --test_output=errors //crates/codescythe_cli:codescythe_cli_e2e_test
• bazel test //...
• git diff --check