perf(diffctx): pass file_cache to edge builder discovery

Thread file_cache dict through discover_all_related_files → edge
builders. PythonEdgeBuilder._build_import_index now reads from
cache instead of disk. Add **kwargs to all 43 discover_related_files
overrides to support optional cache parameter. Eliminates ~3500
redundant file reads per invocation on large Python repos.

Author: nikolay-e

src/treemapper/diffctx/edges/__init__.py

@@ -71,10 +71,11 @@ def discover_all_related_files(
     changed_files: list[Path],
     all_candidate_files: list[Path],
     repo_root: Path | None = None,
+    file_cache: dict[Path, str] | None = None,
 ) -> list[Path]:
     discovered: set[Path] = set()
     for builder in get_all_builders():
-        for f in builder.discover_related_files(changed_files, all_candidate_files, repo_root):
+        for f in builder.discover_related_files(changed_files, all_candidate_files, repo_root, file_cache=file_cache):
             discovered.add(f)
     return list(discovered)
 

src/treemapper/diffctx/edges/base.py

@@ -181,6 +181,7 @@ def discover_related_files(
         changed_files: list[Path],
         all_candidate_files: list[Path],
         repo_root: Path | None = None,
+        **kwargs: object,
     ) -> list[Path]:
         return []
 

src/treemapper/diffctx/edges/config/build.py

@@ -95,6 +95,7 @@ def discover_related_files(
         changed_files: list[Path],
         all_candidate_files: list[Path],
         repo_root: Path | None = None,
+        **kwargs: object,
     ) -> list[Path]:
         make_files = [f for f in changed_files if _is_makefile(f)]
         cmake_files = [f for f in changed_files if _is_cmake(f)]

src/treemapper/diffctx/edges/config/cicd.py

@@ -264,6 +264,7 @@ def discover_related_files(
         changed_files: list[Path],
         all_candidate_files: list[Path],
         repo_root: Path | None = None,
+        **kwargs: object,
     ) -> list[Path]:
         ci_files = [f for f in changed_files if _is_ci_file(f)]
         if not ci_files:

src/treemapper/diffctx/edges/config/docker.py

@@ -91,6 +91,7 @@ def discover_related_files(
         changed_files: list[Path],
         all_candidate_files: list[Path],
         repo_root: Path | None = None,
+        **kwargs: object,
     ) -> list[Path]:
         docker_files = [f for f in changed_files if _is_dockerfile(f) or _is_compose_file(f)]
         if not docker_files:

src/treemapper/diffctx/edges/config/generic.py

@@ -123,6 +123,7 @@ def discover_related_files(
         changed_files: list[Path],
         all_candidate_files: list[Path],
         repo_root: Path | None = None,
+        **kwargs: object,
     ) -> list[Path]:
         config_changed = [f for f in changed_files if _is_config_file(f)]
         if not config_changed:

src/treemapper/diffctx/edges/config/helm.py

@@ -88,6 +88,7 @@ def discover_related_files(
         changed_files: list[Path],
         all_candidate_files: list[Path],
         repo_root: Path | None = None,
+        **kwargs: object,
     ) -> list[Path]:
         templates = [f for f in changed_files if _is_helm_template(f)]
         values = [f for f in changed_files if _is_helm_values(f)]

src/treemapper/diffctx/edges/config/kubernetes.py

@@ -181,6 +181,7 @@ def discover_related_files(
         changed_files: list[Path],
         all_candidate_files: list[Path],
         repo_root: Path | None = None,
+        **kwargs: object,
     ) -> list[Path]:
         k8s_files = _find_k8s_files(changed_files)
         if not k8s_files:

src/treemapper/diffctx/edges/config/terraform.py

@@ -200,6 +200,7 @@ def discover_related_files(
         changed_files: list[Path],
         all_candidate_files: list[Path],
         repo_root: Path | None = None,
+        **kwargs: object,
     ) -> list[Path]:
         tf_files = [f for f in changed_files if _is_terraform_file(f)]
         if not tf_files:

src/treemapper/diffctx/edges/semantic/ansible.py

@@ -104,6 +104,7 @@ def discover_related_files(
         changed_files: list[Path],
         all_candidate_files: list[Path],
         repo_root: Path | None = None,
+        **kwargs: object,
     ) -> list[Path]:
         ansible_changed = [f for f in changed_files if _is_ansible_file(f)]
         if not ansible_changed: