fix: restore develop branch trigger support for CI workflows

Re-adds 'develop' to push triggers in develop.yaml and tests.yaml
so the :develop Docker image can be built from the develop branch,
enabling dev testing without requiring a merge to main.

.gitea/workflows/develop.yaml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - 'main'
+      - 'develop'
 
 jobs:
   docker:

.gitea/workflows/tests.yaml

@@ -4,9 +4,11 @@ on:
   push:
     branches:
       - 'main'
+      - 'develop'
   pull_request:
     branches:
       - 'main'
+      - 'develop'
 
 jobs:
   test: