Rename config templates: .templ → -sim.json.tpl, config_real.json → -real.json.tpl

Consistent naming: config-sim.json.tpl and config-real.json.tpl.
Update README and TODO references accordingly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SH2D4LRuCnhLSzoYerAfJX

components/plant/TODO.md

@@ -24,7 +24,7 @@ the current `delay`-line rewrite of `Pot`.
   wired from `brewpi.py`'s `TempSensorFactory.create(..., temp_offset=
   -0.15, variance=0.01)`), not in the plant model. The stale
   `Model.kn`/`Plant.kn` keys this item flagged have since been deleted
-  from `config.json.templ`/`config.json.sim` too.
+  from `config-sim.json.tpl`/`config.json.sim` too.
 
 - [x] **`theta_amb` is hardcoded, not configured.** Fixed: added a
   top-level `ambient_temperature` key to `config.json`(`.templ`/`.sim`);