docs(privacy): point the controller contact at support@ (#307)

The Controller section of `docs/PRIVACY.md` names the address a reader writes
to in order to exercise their rights under Art. 15-21 GDPR. That is a different
kind of mail from a project enquiry, so it now points at
`support@jeanlucmakiola.de` instead of `business@jeanlucmakiola.de`.

Same change is going into Agendula, and the website's own Datenschutzerklärung
already names `support@` in its § 1. `business@` stays reachable — it is just no
longer the published address anywhere.

`updated:` bumped to 2026-09-15, since the published policy changes.

Two notes for review:

- **Target branch.** CONTRIBUTING says to target the release branch named by the
  issue's milestone. The open milestones (2.21.0 and later) have no branches
  yet, so per the same section this targets `main` and says so — retarget it if
  you would rather it waited for one.
- **No changelog entry.** The entries in `CHANGELOG.md` describe what changed
  for the person using the app, and nothing about the app changed here. Happy to
  add one under a new `## [Unreleased]` if you want the contact change to show
  up in the release notes.

`business@` needs to keep accepting mail until this is live on
jeanlucmakiola.de/calendula/privacy and the Play Console listing has caught up.

Co-authored-by: Jean-Luc Makiola <business@jeanlucmakiola.de>
Reviewed-on: https://codeberg.org/jlmakiola/calendula/pulls/307

docs/PRIVACY.md

@@ -1,7 +1,7 @@
 ---
 title: Privacy Policy — Calendula
 description: What Calendula does with your data. It collects nothing, sends nothing, and has no internet permission at all.
-updated: 2026-07-28
+updated: 2026-09-15
 ---
 
 <!--
@@ -33,7 +33,7 @@ Calendula collects nothing, sends nothing, and has no user accounts. It has **no
 IT-Dienstleister | Jean-Luc Makiola  
 Mahlerstraße 10  
 14772 Brandenburg an der Havel  
-Email: [business@jeanlucmakiola.de](mailto:business@jeanlucmakiola.de)
+Email: [support@jeanlucmakiola.de](mailto:support@jeanlucmakiola.de)
 
 ## 2. No data collection