docs(cli): condense invocation diagnostic guidance

Signed-off-by: Eric Evans <194135482+ericevans-nv@users.noreply.github.com>

Author: ericevans-nv

docs/nemo-relay-cli/basic-usage.mdx

@@ -74,32 +74,22 @@ instead of the built-in shortcut:
 nemo-relay run -- codex
 ```
 
-When `--agent` or an agent shortcut already selects the host, pass only that
-host's arguments after `--`. For example, use:
+When `--agent` or an agent shortcut selects the host, pass only the host's
+arguments after `--`:
 
 ```bash
 nemo-relay run --agent claude -- -p "Review this change"
 ```
 
-Do not repeat the selected executable as the first argument:
+If the selected executable is repeated after `--`, Relay warns and continues
+without modifying the command. Inspect the correction without launching the
+agent:
 
 ```bash
-nemo-relay run --agent claude -- claude -p "Review this change"
+nemo-relay doctor invocation --agent claude -- claude
 ```
 
-Relay reports `possible_duplicate_agent_executable` when the first argument
-after `--` resolves to the agent that Relay already selected. The warning is
-advisory: Relay does not reject or rewrite the command. It does not inspect
-later arguments or prompt content.
-
-Use the invocation doctor to compare the observed and recommended command
-without launching an agent. Arguments are redacted by default; request the full
-command only when it is safe to display potentially sensitive values:
-
-```bash
-nemo-relay doctor invocation --agent claude -- claude -p "Review this change"
-nemo-relay doctor invocation --agent claude --show-full-command -- claude -p "Review this change"
-```
+Arguments are redacted unless `--show-full-command` is explicitly used.
 
 For Claude Code and Codex, transparent mode leaves the caller's source settings,
 selected profile, and installed plugin state unchanged. A process marker makes