fix(robomp): parameterized bot identity in system prompts

system_append.md and system_append_pr_review.md hardcoded the literal
'robomp' as the bot persona, so the agent self-mentioned an account
that does not exist when deployments configure ROBOMP_BOT_LOGIN to a
different login. Affected users saw the agent ask for @robomp mentions
that GitHub never resolved to the actual bot.

Thread the configured login through persona.system_append and
persona.system_append_pr_review as a bot_login keyword, render it
via the existing {{bot_login}} placeholder, and pass
settings.bot_login at the worker callsite. Regression test asserts the
templated login lands in both prompts and the legacy literal is gone.

Fixes #1932

python/robomp/src/worker.py

@@ -512,9 +512,19 @@ def _run_rpc_blocking(
     )
     inputs.db.set_event_model(inputs.delivery_id, chosen_model)
     append_system_prompt = (
-        persona.system_append_pr_review(repo=inputs.repo, issue=inputs.issue, workspace=inputs.workspace)
+        persona.system_append_pr_review(
+            repo=inputs.repo,
+            issue=inputs.issue,
+            workspace=inputs.workspace,
+            bot_login=inputs.settings.bot_login,
+        )
         if task_kind == "review_pr"
-        else persona.system_append(repo=inputs.repo, issue=inputs.issue, workspace=inputs.workspace)
+        else persona.system_append(
+            repo=inputs.repo,
+            issue=inputs.issue,
+            workspace=inputs.workspace,
+            bot_login=inputs.settings.bot_login,
+        )
     )
 
     with RpcClient(