Address PR review comments

- Refactor targetPaths/findOwnPaths to class-based implementations with
  unified caching and .dir/.rootDir properties alongside resolve methods
- Replace jest.mock with jest.spyOn in plugin-manager.test.ts
- Remove paths compatibility wrapper from repo-tools, migrate all internal
  consumers to use targetPaths from @backstage/cli-common directly
- Fix changeset package name (@techdocs/cli not @backstage/techdocs-cli)
- Add migration examples to cli-common changeset
- Update API report for cli-common

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/yarn-plugin/src/index.test.ts

@@ -86,7 +86,7 @@ describe('Backstage yarn plugin', () => {
     let initialLockFileContent: string | undefined;
 
     beforeAll(async () => {
-      const targetRoot = targetPaths.resolveRoot();
+      const targetRoot = targetPaths.rootDir;
       await executeCommand('yarn', ['build'], {
         cwd: joinPath(targetRoot, 'packages/yarn-plugin'),
       });

packages/yarn-plugin/src/util/getWorkspaceRoot.test.ts

@@ -50,6 +50,12 @@ describe('getWorkspaceRoot', () => {
       jest.doMock('@backstage/cli-common', () => ({
         ...jest.requireActual('@backstage/cli-common'),
         targetPaths: {
+          get dir() {
+            return mockResolveRoot();
+          },
+          get rootDir() {
+            return mockResolveRoot();
+          },
           resolveRoot: mockResolveRoot,
         },
       }));

packages/yarn-plugin/src/util/getWorkspaceRoot.ts

@@ -18,5 +18,5 @@ import { npath } from '@yarnpkg/fslib';
 import { targetPaths } from '@backstage/cli-common';
 
 export const getWorkspaceRoot = () => {
-  return npath.toPortablePath(targetPaths.resolveRoot());
+  return npath.toPortablePath(targetPaths.rootDir);
 };