docs(readme): pin CI badge to main and restyle social/coverage badges (#544)

* docs(readme): pin CI badge to main and restyle social/coverage badges

Scope the Vocalinux CI status badge to the main branch so PR failures no
longer flip the README shield. Restyle the X follow badge to black/white X
aesthetics, and set Codecov coverage.range so 80%+ coverage shows green.

* docs(readme): use static X follow badge without broken count

Shields.io no longer returns Twitter/X follower counts (empty right-side
value after API restrictions). Switch to a static black badge that shows
Follow @jatinkrmalik with the X logo instead of an empty dynamic count.

README.md

@@ -18,10 +18,10 @@
 [![AUR](https://img.shields.io/aur/version/vocalinux)](https://aur.archlinux.org/packages/vocalinux)
 
 <!-- Quality + social -->
-[![Vocalinux CI](https://github.com/jatinkrmalik/vocalinux/workflows/Vocalinux%20CI/badge.svg)](https://github.com/jatinkrmalik/vocalinux/actions)
+[![Vocalinux CI](https://github.com/jatinkrmalik/vocalinux/actions/workflows/unified-pipeline.yml/badge.svg?branch=main)](https://github.com/jatinkrmalik/vocalinux/actions/workflows/unified-pipeline.yml?query=branch%3Amain)
 [![Python 3.9+](https://img.shields.io/badge/python-3.9+-blue.svg)](https://www.python.org/downloads/)
 [![codecov](https://codecov.io/gh/jatinkrmalik/vocalinux/branch/main/graph/badge.svg)](https://codecov.io/gh/jatinkrmalik/vocalinux)
-[![Twitter Follow](https://img.shields.io/twitter/follow/jatinkrmalik?style=social)](https://x.com/intent/user?screen_name=jatinkrmalik)
+[![Follow on X](https://img.shields.io/badge/Follow%20%40jatinkrmalik-000000?style=flat&logo=x&logoColor=white)](https://x.com/intent/user?screen_name=jatinkrmalik)
 
 <!-- Distros (widest; base plate above the hero) -->
 [![Ubuntu](https://img.shields.io/badge/Ubuntu-22.04+-E95420?logo=ubuntu&logoColor=white)](docs/DISTRO_COMPATIBILITY.md)

codecov.yml

@@ -1,4 +1,8 @@
 coverage:
+  # Badge colors: red below 50%, yellow 50–80%, green at 80%+ (matches project target)
+  range: 50..80
+  round: down
+  precision: 2
   status:
     project:
       default: