feat: add well-known files classifier for repo enricher

Signed-off-by: Mouad BANI <mouad-mb@outlook.com>

Author: mbani01

services/apps/packages_worker/src/enricher/wellKnownFiles.ts

@@ -0,0 +1,72 @@
+export type WellKnownFileType =
+  | 'security'
+  | 'contributing'
+  | 'governance'
+  | 'maintainers'
+  | 'code_of_conduct'
+  | 'readme'
+
+export type WellKnownDirectory = 'root' | '.github' | 'docs'
+
+export interface TreeEntryNode {
+  name: string
+  type: string
+  oid: string
+}
+
+export interface WellKnownFileEntry {
+  fileType: WellKnownFileType
+  directory: WellKnownDirectory
+  path: string
+  blobOid: string
+}
+
+export interface RepoTrees {
+  root: TreeEntryNode[] | null
+  github: TreeEntryNode[] | null
+  docs: TreeEntryNode[] | null
+}
+
+const STEM_TO_TYPE: Record<string, WellKnownFileType> = {
+  README: 'readme',
+  SECURITY: 'security',
+  CONTRIBUTING: 'contributing',
+  GOVERNANCE: 'governance',
+  MAINTAINERS: 'maintainers',
+  CODEOWNERS: 'maintainers',
+  CODE_OF_CONDUCT: 'code_of_conduct',
+}
+
+function stemOf(filename: string): string {
+  return filename
+    .replace(/\.[^.]+$/, '')
+    .toUpperCase()
+    .replace(/-/g, '_')
+}
+
+const DIRECTORIES: Array<{ key: keyof RepoTrees; directory: WellKnownDirectory; prefix: string }> =
+  [
+    { key: 'root', directory: 'root', prefix: '' },
+    { key: 'github', directory: '.github', prefix: '.github/' },
+    { key: 'docs', directory: 'docs', prefix: 'docs/' },
+  ]
+
+export function classifyWellKnownFiles(trees: RepoTrees): WellKnownFileEntry[] {
+  const result: WellKnownFileEntry[] = []
+  for (const { key, directory, prefix } of DIRECTORIES) {
+    for (const entry of trees[key] ?? []) {
+      if (entry.type !== 'blob') continue
+      const fileType = STEM_TO_TYPE[stemOf(entry.name)]
+      if (!fileType) continue
+      result.push({ fileType, directory, path: prefix + entry.name, blobOid: entry.oid })
+    }
+  }
+  return result
+}
+
+// Mirrors the retired REST probe so repos.security_file_enabled semantics don't shift
+export function deriveSecurityFileEnabled(trees: RepoTrees): boolean {
+  return [...(trees.root ?? []), ...(trees.github ?? [])].some(
+    (entry) => entry.type === 'blob' && entry.name.toUpperCase() === 'SECURITY.MD',
+  )
+}