test(perf): overhaul performance and memory baseline management

Comprehensive automation upgrades for performance and memory baselines. Includes GitHub Actions workflows for remote updates, automatic local comparisons against main, and git-ignored temporary baselines.

- Added update-baselines.yml GitHub Action to automate remote baseline upgrades efficiently in CI.
- Created scripts/run-perf-tests.js to wrap performance executions, safely stashing dirty alterations and gathering main-branch baselines locally when run without arguments.
- Enhanced PerfTestHarness and MemoryTestHarness to accommodate tolerance limits assertions safely.
- Updated test files to process TEMP_BASELINES_PATH environment variables, protecting tracked files clean during local evaluations.
- Formed docs/performance-and-memory-testing.md safely centrally detailing general strategies.
- Obsoleted folder files perf-tests/README.md, and memory-tests/README.md deleted altogether.
- Registered temporary baseline outputs inside .gitignore and updated scripts/clean.js safely for fast removals on npm run clean.

.github/workflows/memory-nightly.yml

@@ -10,9 +10,21 @@ permissions:
 
 jobs:
   memory-test:
-    name: 'Run Memory Usage Tests'
-    runs-on: 'gemini-cli-ubuntu-16-core'
+    name: 'Run Memory Usage Tests (${{ matrix.machine_family }})'
     if: "github.repository == 'google-gemini/gemini-cli'"
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - runs_on: 'gemini-cli-ubuntu-16-core'
+            machine_family: 'gemini-cli-ubuntu-16-core'
+          - runs_on: 'macos-latest'
+            machine_family: 'macos-latest'
+          - runs_on: 'gemini-cli-windows-16-core'
+            machine_family: 'gemini-cli-windows-16-core'
+    runs-on: '${{ matrix.runs_on }}'
+    env:
+      MEMORY_MACHINE_FAMILY: '${{ matrix.machine_family }}'
     steps:
       - name: 'Checkout'
         uses: 'actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8' # ratchet:actions/checkout@v5