feat(cli): report opt-in command timings (#7042)

* feat(cli): report opt-in command timings

* fix(cli): time standalone MCP doctor

* fix(cli): retain timing on doctor errors

* fix(cli): preserve formatted version output with command timings

---------

Co-authored-by: dhruvac29 <dhruvac29@users.noreply.github.com>
Co-authored-by: gensokyo-dev <342580529+gensokyo-dev@users.noreply.github.com>

docs/cli.md

@@ -51,6 +51,15 @@ module page. See
 [JavaScript application workflows](javascript-application-workflows.md) for
 views, feature traces and comparisons that take the same saved Evidence.
 
+Add `--timings` to a command to write one JSON timing record to stderr. For
+example, `rea inspect-elf-notes program --json --timings > result.json` keeps
+stdout as a parseable result and writes
+`{"rea_timings":{"version":1,"command_ms":42}}` to stderr. `command_ms`
+measures CLI command dispatch and result delivery; it is not provider-only or
+analysis-only time. The flag is off by default, and the record omits stages
+that REA did not measure. Root version reporting does not dispatch a command
+and has no command timing record.
+
 ## JSON Lines record output
 
 Use `--format jsonl` to consume row-oriented results one record per line: