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/web/src/pages/login-page.tsx

@@ -25,7 +25,7 @@ export function LoginPage() {
       const data = await res.json();
       setToken(data.token);
       // Store username for settings display
-      localStorage.setItem("stirling-username", data.user?.username || username);
+      localStorage.setItem("ashim-username", data.user?.username || username);
       // Redirect to password change if required, otherwise go home
       if (data.user?.mustChangePassword) {
         window.location.href = "/change-password";
@@ -45,7 +45,7 @@ export function LoginPage() {
         <div className="w-full max-w-md space-y-8">
           <div>
             <h1 className="text-3xl font-bold text-foreground">
-              Stirling <span className="text-primary">Image</span>
+              <span className="text-primary">ashim</span>
             </h1>
             <h2 className="text-2xl font-bold mt-4 text-foreground">Login</h2>
           </div>