fix(ci): run static analysis for every tree the repo-wide audits scan (#20918)

A mobile-only diff is desktop-irrelevant, so should_run was false and every PR check skipped -- including the audits that do lint mobile/. The violation then landed on main and failed the same gate on every later PR's merge ref. Derive the trigger from the audit commands' own scan roots so the two cannot drift.

config/scripts/pr-code-change-scope.test.mjs

@@ -7,7 +7,8 @@ import {
   classifyPrJobs,
   isDocsOnlyPath,
   PR_CHECK_JOBS,
-  shouldRunPrChecks
+  shouldRunPrChecks,
+  STATIC_ANALYSIS_SCAN_ROOTS
 } from './pr-code-change-scope.mjs'
 
 const projectDir = resolve(import.meta.dirname, '../..')
@@ -327,11 +328,41 @@ describe('per-job path classification', () => {
     expect(
       classifyPrJobs(['src/main/index.ts', 'mobile/src/session/a.test.ts']).mobile_dependencies
     ).toBe(true)
-    // Why false: a mobile-only diff skips every desktop job, so the install step's own
-    // job never runs and claiming the install is needed contradicts should_run.
-    expect(classifyPrJobs(['mobile/package.json']).mobile_dependencies).toBe(false)
+    // Why true: a mobile-only diff still skips the desktop suite, but the repo-wide audits lint
+    // mobile/, so static analysis runs and its changed-code pass needs the mobile types.
+    expect(classifyPrJobs(['mobile/package.json']).mobile_dependencies).toBe(true)
     expect(classifyPrJobs(['mobile/package.json']).should_run).toBe(false)
-    expect(classifyPrJobs(['README.md', 'mobile/src/a.ts']).mobile_dependencies).toBe(false)
+    expect(classifyPrJobs(['README.md', 'mobile/src/a.ts']).mobile_dependencies).toBe(true)
+  })
+
+  // Why: `mobile/` is desktop-irrelevant for every other job, so a mobile-only diff used to skip
+  // the audits that do lint it. That is how #20702 landed two duplicate imports which then failed
+  // this gate on every later PR's merge ref until #20895 swept them.
+  it('runs static analysis for a mobile-only diff without dragging in the desktop suite', () => {
+    const result = classifyPrJobs([
+      'mobile/src/test-support/rpc-recording/adapters/push-registration-mount-adapters.ts'
+    ])
+    expect(result.static_analysis).toBe(true)
+    expect(result.mobile_dependencies).toBe(true)
+    expect(result.should_run).toBe(false)
+    for (const job of ['typecheck', 'test', 'package', 'package_windows', 'git_compatibility']) {
+      expect(result[job], job).toBe(false)
+    }
+  })
+
+  // The ratchet: adding a tree to an audit command has to widen this trigger on its own.
+  it('runs static analysis for every tree the audit commands scan', () => {
+    expect(STATIC_ANALYSIS_SCAN_ROOTS).toEqual(
+      expect.arrayContaining(['src', 'config', 'tests', 'mobile'])
+    )
+    for (const root of STATIC_ANALYSIS_SCAN_ROOTS) {
+      expect(classifyPrJobs([`${root}/changed-file.ts`]).static_analysis, root).toBe(true)
+    }
+  })
+
+  it('leaves diffs the audits never read out of static analysis', () => {
+    expect(classifyPrJobs(['README.md']).static_analysis).toBe(false)
+    expect(classifyPrJobs(['cloud/apps/relay/src/index.ts']).static_analysis).toBe(false)
   })
 
   it('keeps unit-test-only diffs out of packaging', () => {