docs(growth-report): drop reference to the local SDK-preservation branch

The chargeback-only READMEs referenced a `growth-report-sdk-full` branch that
exists only locally (not pushed), which is confusing for external readers.
Remove the mention; the retired-SDK context isn't needed in shipped docs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: LeoRoccoBreedt

README-ADMIN.md

@@ -132,9 +132,7 @@ of workspaces, users, and platform adoption, broken down by workspace/department
 
 **Requires an admin API key.** The report is derived entirely from the admin
 chargeback endpoint; with a non-admin key the command prints an error and exits
-non-zero — there is no fallback. (An earlier SDK/platform-direct methodology that
-collected per-workspace Opik/EM/MPM data has been retired from this command and
-is preserved on the local `growth-report-sdk-full` git branch.)
+non-zero — there is no fallback.
 
 ### Basic Usage
 

README.md

@@ -587,9 +587,7 @@ workspaces, users, and platform adoption, per workspace/department.
 
 **Requires an admin API key** — the report is derived entirely from the admin
 chargeback endpoint, and with a non-admin key the command errors out (non-zero
-exit). The earlier SDK/platform-direct methodology (per-workspace Opik/EM/MPM
-collection) has been retired from this command and is preserved on the local
-`growth-report-sdk-full` git branch.
+exit).
 
 ```
 cometx admin growth-report [WORKSPACE ...]