refactor(config): adopt config-loader-facade across the codebase

Issue #1161. Sweeps 127 files to import from
src/config/config-loader-facade.ts instead of unified-config-loader or
utils/config-manager directly.

WRITE callers (32 files): replaced raw saveUnifiedConfig /
mutateUnifiedConfig / updateUnifiedConfig calls with the facade's
cache-coherent wrappers saveConfig / mutateConfig / updateConfig. This
fixes a latent stale-cache window where direct writes through the
underlying loader bypassed the facade's memoization.

READ callers (95 files): mechanical import-path migration only —
function names unchanged because the facade re-exports them. No
behavior change.

Also updated:
- tests/unit/utils/browser/browser-setup.test.ts (DI interface rename)
- src/management/checks/image-analysis-check.ts (dynamic import rename)
- src/web-server/health-service.ts (dynamic require rename)
- src/ccs.ts (path prefix fix from sweep script)

After sweep: zero raw write callers remain outside src/config/. Direct
imports of config-manager remain only for symbols not in the facade
(getConfigPath, getCcsDirSource, etc). Behavior unchanged; full suite
passes 1824/1824.

Out of scope: switching loadOrCreateUnifiedConfig() callers to
getCachedConfig() — needs per-callsite cache-safety analysis. Tracked
as follow-up.

Refs #1161

src/auth/commands/remove-command.ts

@@ -8,10 +8,11 @@ import * as fs from 'fs';
 import * as path from 'path';
 import { initUI, color, ok, fail, info } from '../../utils/ui';
 import { InteractivePrompt } from '../../utils/prompt';
-import { isUnifiedMode } from '../../config/unified-config-loader';
+
 import { exitWithError } from '../../errors';
 import { ExitCode } from '../../errors/exit-codes';
 import { CommandContext, parseArgs } from './types';
+import { isUnifiedMode } from '../../config/config-loader-facade';
 
 /**
  * Handle the remove command