Migrate to vitest: session.ts orchestrator + drop node:test

[thymikee]

Step 4 of 4: Drop test-only DI with vitest module mocking

Final step. By now all sub-handlers own their imports directly — the orchestrator params have no consumers left.

Files to migrate (~24 DI params removed)

src/daemon/handlers/session.ts (18 optional params)

• Remove all optional DI params from handleSessionCommands:
  dispatch?, ensureReady?, resolveTargetDevice?, installOps?, reinstallOps?, stopIosRunner?, dismissMacOsAlert?, appLogOps?, ensureAndroidEmulatorBoot?, resolveAndroidPackageForOpen?, applyRuntimeHints?, clearRuntimeHints?, settleSimulator?, shutdownSimulator?, shutdownAndroidEmulator?, listAndroidDevices?, listAppleDevices?, listAppleApps?
• Remove ~6 required threaded params from internal functions (runSessionOrSelectorDispatch, handleClipboardCommand, maybeResolvePushPayloadPath wiring, etc.)
• All *Override local aliases (dispatchOverride, ensureReadyOverride, etc.) collapse to direct imports

Tests to rewrite:

• handlers/__tests__/session.test.ts (main orchestrator tests)
• Any remaining node:test files

Drop node:test runner

• Remove node:test from CI config
• Remove any dual-runner configuration from vitest.config.ts
• Convert any stragglers still using node:test + node:assert

Add permanent CI lint guard

# Fail if test-only DI seams reappear in production code
rg '\?\s*:\s*typeof\s+' src/ --glob '!**/__tests__/**' --glob '!*.test.ts'

Validation

• pnpm typecheck
• pnpm test:unit (vitest only now)
• pnpm test:smoke
• Lint guard passes with zero matches

Expected result

• ~99 typeof DI params removed across ~20 production files
• Test files use vi.mock instead of constructing DI param bags
• handleSessionCommands signature drops from ~30 params to ~5 (req, sessionName, sessionStore, logPath, invoke)

Depends on #283. Part of migration: #1→#2→#3→**#4**