core/cli: show estimated context tokens and usage source tags

/status adds context_tokens~=(est); docs note api/estimate/mixed labels.

src/plyngent/cli/repl.py

@@ -60,8 +60,11 @@ def _cmd_status(state: ReplState) -> None:
     pending_disp = "yes" if pending else "no"
     ctx_chars = estimate_messages_chars(state.agent.messages)
     ctx_budget = state.agent.max_context_chars
+    from plyngent.agent.usage import chars_to_tokens
+
     session_u = state.agent.session_usage
     last_u = state.agent.last_turn_usage
+    ctx_est_tokens = chars_to_tokens(ctx_chars)
     click.echo(
         f"provider={state.provider_name}  model={state.model}\n"
         f"session={state.session_id}  messages={len(state.agent.messages)}  "
@@ -69,6 +72,7 @@ def _cmd_status(state: ReplState) -> None:
         f"tools={'on' if state.tools_enabled else 'off'}  "
         f"rounds={state.max_rounds}  stream={'on' if state.agent.stream else 'off'}\n"
         f"context_chars={ctx_chars}/{ctx_budget}  "
+        f"context_tokens~={ctx_est_tokens} (est)  "
         f"tool_result_max={state.agent.max_tool_result_chars}\n"
         f"usage_session={session_u.format_line()}\n"
         f"usage_last_turn={last_u.format_line()}\n"