docs: old product name F∆I Platform -> Ch∆In

The product is Ch∆In; the old 'F∆I Platform' name survived in module
docs/manifests. Generic 'platform' terms left untouched.

Signed-off-by: flemming-it <sf@flemming.it>

.forgejo/workflows/sign.yml

@@ -151,7 +151,7 @@ jobs:
             3. Paste the unencrypted PEM (BEGIN PRIVATE KEY ...)
           The encrypted source-of-truth lives on Stefan's Mac at
           ~/.fai-secrets/flemming-ai-signing.key (passphrase in
-          mSecure under "F∆I Platform — Module Signing Key (Private)").
+          mSecure under "Ch∆In — Module Signing Key (Private)").
 
           See fai/platform infra/cosign/OPERATOR-HANDOFF.md for the
           full setup runbook and rotation process.

README.md

@@ -1,6 +1,6 @@
 # text-translate
 
-Provides the `text.translate` capability for F∆I Platform.
+Provides the `text.translate` capability for Ch∆In.
 
 ## Build