docs: rewrite cleanup-instructions in a calmer voice

The pre-v0.1.20 upgrade note had vented frustration in it. Same substance
(uninstall + reinstall is the supported path; reach out for large fleets),
without the curt phrasing.

README.md

@@ -333,7 +333,7 @@ It's about: **80% of the functionality for 0% of the cost, plus 3 security advan
 
 ### Removing Old Versions (Pre-v0.1.20)
 
-If you're upgrading from versions older than v0.1.20, old agent installations used different paths. It it highly recommended to just uninstall the old version (instructions are below... and yet, for some idiotic reason I have tried to implement this early stage migration - but  it's not going to work... don't try that unless you like pain, just uninstall, you can't have more than like... 100 agents already yeah? if so... call me) see below:
+If you're upgrading from versions older than v0.1.20, old agent installations used different paths. We recommend uninstalling the old version and reinstalling fresh rather than trying to migrate in place — the early-stage migration path is not reliable and a clean reinstall is the supported route. If you have a large fleet (more than ~100 agents) and an in-place migration would be valuable for you, please reach out and we'll work with you on it.
 
 **Old Agent Locations (to remove if present):**
 - `/etc/aggregator/` - Old agent configuration directory
@@ -368,7 +368,7 @@ Remove-Item "C:\ProgramData\Aggregator\*" -Recurse -ErrorAction SilentlyContinue
 iwr https://your-server.com/install.ps1 | iex
 ```
 
-### Full Fresh Install (If Things Are Messy)
+### Full Fresh Install (Clean State)
 
 If you want to completely remove everything and start fresh: