ci(build): use apt-get with correct Ubuntu package names

Replace apt with apt-get, add -y flag, fix Alpine-style package names
(py3-pip → python3-pip, docker-cli → docker.io), and drop musl-dev.

.gitea/workflows/build.yaml

@@ -15,7 +15,7 @@ jobs:
       - name: Install system dependencies
         shell: sh
         run: |
-          apt update && apt install git python3 py3-pip gcc musl-dev libpq-dev python3-dev
+          apt-get update && apt-get install -y git python3 python3-pip gcc libpq-dev python3-dev
 
       - name: Checkout code
         shell: sh
@@ -36,7 +36,7 @@ jobs:
       - name: Install Node.js and check TypeScript types
         shell: sh
         run: |
-          apt install nodejs npm
+          apt-get install -y nodejs npm
           cd frontend
           npm ci
           npm run generate:local
@@ -65,7 +65,7 @@ jobs:
       - name: Install dependencies
         shell: sh
         run: |
-          apt install git docker-cli
+          apt-get install -y git docker.io
 
       - name: Checkout code
         shell: sh
@@ -137,7 +137,7 @@ jobs:
       - name: Install dependencies
         shell: sh
         run: |
-          apt install git docker-cli
+          apt-get install -y git docker.io
 
       - name: Checkout code
         shell: sh