Multi-arch release script + Gitea workflow; retire legacy BunSCP name

bun run release -- --target mac-arm64|mac-x64|win-x64: gen version/icons,
build UI, electrobun build --env=stable, collect artifacts as
release/<target>/miniSCP-Build<n>-<target>.*. mac-x64 builds on the
arm64 Mac by running electrobun's x64 CLI under Rosetta 2 (verified:
x86_64 launcher in the produced app). Windows also zips a portable
build next to the Setup installer. Tag-triggered Gitea Actions matrix
included, inert until runners exist. legacyNames emptied — the BunSCP
migration has served its purpose.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -87,6 +87,29 @@ This starts the Angular dev server (hot reload for UI code) and launches the
 Electrobun app pointed at it. Edits under `ui/` reload instantly; edits to the
 Bun main process (`src/bun/**`, RPC schema) trigger an app relaunch.
 
+## Releases
+
+Versioning is Sublime-style: **Build n**, where n is the commit count
+(`git rev-list --count HEAD`), regenerated into the gitignored
+`src/shared/version.gen.ts` by every build script (and `postinstall`).
+
+One artifact per invocation, on the matching host — electrobun cannot
+cross-compile between OSes:
+
+```sh
+bun run release -- --target mac-arm64   # on the Mac (native)
+bun run release -- --target mac-x64     # on the same arm64 Mac, via Rosetta 2
+bun run release -- --target win-x64     # on a Windows 11 x64 machine
+```
+
+Artifacts land in `release/<target>/miniSCP-Build<n>-<target>.*` — a `.dmg`
+per mac arch; on Windows a `-Setup.zip` installer **and** a `-portable.zip`
+(unzip anywhere and run). The mac-x64 build fetches electrobun's x64 CLI once
+into `~/.cache/miniscp/` and runs it under Rosetta so the whole pipeline
+believes it is on an Intel Mac. CI: `.gitea/workflows/release.yml` runs the
+same script on a macos + windows runner matrix once act_runners are
+registered; trigger by pushing a `build-<n>` tag.
+
 ## Build a packaged app
 
 ```bash
@@ -109,7 +132,7 @@ Everything user-facing reads from **[`src/shared/branding.ts`](src/shared/brandi
 export const BRANDING = {
   appName: "miniSCP",          // window title, bundle name, app-data folder
   identifier: "es.teknes.miniscp",
-  legacyNames: ["BunSCP"],     // previous names; their data dirs migrate on boot
+  legacyNames: [],             // previous names; their data dirs migrate on boot
   version: "0.1.0",
   icon: "assets/icon.iconset",
 } as const;