docs(ci): use the actual case-sensitive SonarQube project keys

link and Android-app reuse the pre-existing capitalised keys
(Runic-Gateway-link, Runic-Gateway-Android-app); the server rejects
case-variant duplicates. Note the case-sensitivity gotcha.

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

ci/SONARQUBE.md

@@ -16,8 +16,13 @@ feeds the dashboard.
 | Repo | Project key | Sources analysed | Language |
 |---|---|---|---|
 | `website` | `runic-gateway-website` | `server/src`, `client/src`, `bot/src` | JS/TS |
-| `link` | `runic-gateway-link` | `sidecar/src` | Rust |
-| `Android-app` | `runic-gateway-android-app` | `app/src/main` | Kotlin |
+| `link` | `Runic-Gateway-link` | `sidecar/src` | Rust |
+| `Android-app` | `Runic-Gateway-Android-app` | `app/src/main` | Kotlin |
+
+> Project keys are **case-sensitive** and must match what already exists on the
+> server — SonarQube refuses to create a key that differs only in case from an
+> existing one. `link` and `Android-app` reuse the pre-existing capitalised keys
+> above; `website` predates this note with its lower-case key.
 
 ## How it's wired