chore: replace em dashes with hyphens, add no-em-dash rule to CLAUDE.md

docs/hq/billing.md

@@ -27,7 +27,7 @@ The instance is created and licensed as soon as payment confirms.
 
 ### Self-hosted
 
-Install your control plane first — a licence binds to its instance ID.
+Install your control plane first - a licence binds to its instance ID.
 
 1. Set **Deployment** to **Self-hosted**.
 2. Choose a **Plan** and configure its features and server allowance.

docs/hq/self-hosted-instances.md

@@ -15,7 +15,7 @@ Install first, then link and claim. Step by step in
 ## Paid
 
 **Install first.** A licence is issued to one instance, so your control plane
-has to exist and report an instance ID before you can buy for it — the same
+has to exist and report an instance ID before you can buy for it - the same
 precondition Free has.
 
 ```mermaid
@@ -36,7 +36,7 @@ flowchart LR
 
 ## Upgrading an instance you already have
 
-Paste the same instance ID you already hold — an install on Free moves to the
+Paste the same instance ID you already hold - an install on Free moves to the
 paid plan in place, keeping its ID and its history. An ID belonging to another
 account is refused.