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/change-password-page.tsx

@@ -99,7 +99,7 @@ export function ChangePasswordPage() {
       }
 
       // Trigger browser password save prompt via real form submission + navigation
-      const username = localStorage.getItem("stirling-username") || "admin";
+      const username = localStorage.getItem("ashim-username") || "admin";
       triggerBrowserPasswordSave(username, newPassword);
       return; // navigation happens inside triggerBrowserPasswordSave
     } catch {
@@ -115,7 +115,7 @@ export function ChangePasswordPage() {
         <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">Change your password</h2>
             <p className="text-sm text-muted-foreground mt-2">
@@ -133,7 +133,7 @@ export function ChangePasswordPage() {
                 type="text"
                 name="username"
                 autoComplete="username"
-                value={localStorage.getItem("stirling-username") || "admin"}
+                value={localStorage.getItem("ashim-username") || "admin"}
                 readOnly
                 className="w-full px-4 py-3 rounded-lg border border-border bg-muted text-muted-foreground cursor-not-allowed"
               />