chore: rename Stirling-Image to ashim across entire codebase

Complete rebrand from Stirling-Image to ashim following the project
move to https://github.com/ashim-hq/ashim.

Changes across 117 files:
- Package scope: @stirling-image/* → @ashim/*
- GitHub URLs: stirling-image/stirling-image → ashim-hq/ashim
- Docker Hub: stirlingimage/stirling-image → ashimhq/ashim
- GitHub Pages: stirling-image.github.io → ashim-hq.github.io
- All branding text: "Stirling Image" → "ashim"
- Docker service/volumes/user: stirling → ashim
- Database: stirling.db → ashim.db
- localStorage keys: stirling-token → ashim-token
- Environment variables: STIRLING_GPU → ASHIM_GPU
- Python cache dirs: .cache/stirling-image → .cache/ashim
- SVG filter IDs, test prefixes, and all other references

apps/docs/.vitepress/theme/GitHubStars.vue

@@ -2,11 +2,11 @@
 import { onMounted, ref } from "vue";
 
 const stars = ref<string | null>(null);
-const repo = "https://github.com/stirling-image/stirling-image";
+const repo = "https://github.com/ashim-hq/ashim";
 
 onMounted(async () => {
   try {
-    const res = await fetch("https://api.github.com/repos/stirling-image/stirling-image");
+    const res = await fetch("https://api.github.com/repos/ashim-hq/ashim");
     if (!res.ok) return;
     const data = await res.json();
     const count = data.stargazers_count;