Show the README without Gitea's Unicode warnings (#426)

The repo's start page marked eight characters in the README and
offered an Escape button. All eight were en dashes (U+2013), which
Gitea flags as ambiguous because they look like a hyphen. The wiki
dropped them in #416, the README now follows the same rule.

- Prose: the dash became a colon, a comma or a full stop.
- Comments in the code blocks: a semicolon.

Tests:
- grep over README.md for en dash, em dash, times, minus and
  single guillemet finds nothing.
- prettier --check README.md is clean.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -3,14 +3,14 @@
 [![feuerwerk](https://git.nockal.com/meleki/feuerwerk/actions/workflows/ci.yml/badge.svg?branch=main)](https://git.nockal.com/meleki/feuerwerk/actions?workflow=ci.yml)
 
 A browser-based tool "one step before a game engine": create **assets** (scenes, cameras,
-sprites), place them into scenes, tweak their properties in an inspector and press **Play** –
+sprites), place them into scenes, tweak their properties in an inspector and press **Play**,
 all in one program, all drawn inside a single WebGL canvas.
 
 ![](screenshot.png)
 
 Live: <https://nockal.com/feuerwerk/> · Widget playground: <https://nockal.com/feuerwerk/?playground>
 
-**The documentation is the wiki:** <https://git.nockal.com/meleki/feuerwerk/wiki> – every concept,
+**The documentation is the wiki:** <https://git.nockal.com/meleki/feuerwerk/wiki>: every concept,
 node, tab and shortcut, plus the architecture and the development workflow. This file is the short
 way in.
 
@@ -25,7 +25,7 @@ way in.
 - A **container** is a reusable group edited once and placed many times; its content is resolved
   from the template on every read. A **screen** is a container switched on and off.
 - A **behavior** is logic as a node graph, placed like anything else and parented to the object it
-  acts on. Play has no built-in behaviour – everything that happens is a graph.
+  acts on. Play has no built-in behaviour: everything that happens is a graph.
 - An **account** owns projects: the editor asks for a user name and a password first, and each
   account sees only its own projects. The Account menu at the far right of the toolbar changes
   the password and signs out.
@@ -39,8 +39,8 @@ Node 22 is required.
 
 ```bash
 npm install
-npm run dev          # http://localhost:5175/feuerwerk/dist/ – API calls are proxied to production
+npm run dev          # http://localhost:5175/feuerwerk/dist/; API calls are proxied to production
-npm run check        # typecheck + lint + format:check + unit tests – the gate CI runs too
+npm run check        # typecheck + lint + format:check + unit tests; the gate CI runs too
 npm run build        # writes dist/ and regenerates index.html; the folder is what nginx serves
 ```
 
@@ -48,14 +48,14 @@ The browser suite and the three example games need a machine with a GPU:
 
 ```bash
 node tools/seed-e2e.mjs && node tools/e2e.mjs      # the editor, 2090 checks (GM_STEPS=20 for one step)
-                                                   #   every tool signs in first – see the Accounts page
+                                                   #   every tool signs in first; see the Accounts page
 node tools/seed-jumprun.mjs && node tools/smoke-jumprun.mjs
 node tools/seed-tetris.mjs && node tools/smoke-tetris.mjs
 node tools/seed-actor.mjs && node tools/smoke-actor.mjs
 ```
 
-Every push runs all of it on the Gitea runners – the gate as one job, build and suite as another
+Every push runs all of it on the Gitea runners: the gate as one job, build and suite as another
-beside it – so locally take the gate plus the step your change touches and leave the full run to
+beside it. So locally take the gate plus the step your change touches and leave the full run to
 CI. Details, the GPU requirement and the detached runner are in
 [Development](https://git.nockal.com/meleki/feuerwerk/wiki/Development).