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/guide/database.md

@@ -1,8 +1,8 @@
 # Database
 
-Stirling Image uses SQLite with [Drizzle ORM](https://orm.drizzle.team/) for data persistence. The schema is defined in `apps/api/src/db/schema.ts`.
+ashim uses SQLite with [Drizzle ORM](https://orm.drizzle.team/) for data persistence. The schema is defined in `apps/api/src/db/schema.ts`.
 
-The database file lives at the path set by `DB_PATH` (defaults to `./data/stirling.db`). In Docker, mount the `/data` volume to persist it across container restarts.
+The database file lives at the path set by `DB_PATH` (defaults to `./data/ashim.db`). In Docker, mount the `/data` volume to persist it across container restarts.
 
 ## Tables
 
@@ -90,7 +90,7 @@ Key-value store for server-wide settings that admins can change from the UI.
 Drizzle handles schema migrations. The config is in `apps/api/drizzle.config.ts`. During development, run:
 
 ```bash
-pnpm --filter @stirling-image/api drizzle-kit push
+pnpm --filter @ashim/api drizzle-kit push
 ```
 
 In production, the schema is applied automatically on startup.