update workflows: remove redundant os input, set ubuntu-latest as default runner in pre-commit jobs

Author: allnes

.github/workflows/ci-orchestrator.yml

@@ -12,11 +12,9 @@ on:
         default: 'emulator-5554'
 
 jobs:
-  # Stage 1: Pre-commit checks
+  # Stage 1: Pre-commit checks (always runs on ubuntu-latest)
   pre-commit:
     uses: ./.github/workflows/stage-pre-commit.yml
-    with:
-      os: ubuntu-latest
     secrets: inherit
 
   # Stage 2: Test

.github/workflows/stage-pre-commit.yml

@@ -2,14 +2,10 @@ name: Pre-commit
 
 on:
   workflow_call:
-    inputs:
-      os:
-        required: true
-        type: string
 
 jobs:
   pre-commit:
-    runs-on: ${{ inputs.os }}
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
         with: