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/components/layout/app-layout.tsx

@@ -61,7 +61,7 @@ export function AppLayout({ children, showToolPanel = true, onFiles }: AppLayout
                 <div className="flex items-center gap-2">
                   <GemLogo className="h-5 w-5 text-primary" />
                   <span className="text-sm font-bold text-foreground">
-                    Stirling <span className="text-primary">Image</span>
+                    <span className="text-primary">ashim</span>
                   </span>
                 </div>
               )}
@@ -109,7 +109,7 @@ export function AppLayout({ children, showToolPanel = true, onFiles }: AppLayout
             <div className="flex items-center gap-2">
               <GemLogo className="h-5 w-5 text-primary" />
               <span className="text-sm font-bold text-foreground">
-                Stirling <span className="text-primary">Image</span>
+                <span className="text-primary">ashim</span>
               </span>
             </div>
           )}

apps/web/src/components/layout/tool-panel.tsx

@@ -1,4 +1,4 @@
-import { CATEGORIES, TOOLS } from "@stirling-image/shared";
+import { CATEGORIES, TOOLS } from "@ashim/shared";
 import { useEffect, useMemo, useState } from "react";
 import { useSettingsStore } from "@/stores/settings-store";
 import { SearchBar } from "../common/search-bar";