ci: give workflows and jobs descriptive names

.github/workflows/build-images.yml

@@ -2,7 +2,7 @@
 #   push to main          -> tags `main` and `sha-<commit>`
 #   Run workflow (Actions) -> tags `<branch>` and `sha-<commit>`, for testing a branch on a robot
 #   pull request          -> build only, nothing is published
-name: Build images
+name: Images
 
 on:
   push:
@@ -24,6 +24,7 @@ env:
 
 jobs:
   pc:
+    name: build pc
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v7
@@ -56,6 +57,7 @@ jobs:
           cache-to: ${{ env.PUSH == 'true' && format('type=registry,ref={0}/pc:buildcache,mode=max', env.REGISTRY) || '' }}
 
   robot:
+    name: build robot
     runs-on: ubuntu-24.04-arm
     steps:
       - uses: actions/checkout@v7

.github/workflows/cleanup-images.yml

@@ -1,6 +1,6 @@
 # Deletes the images of a branch from ghcr.io/kpi-rover when the branch is deleted.
 # Images that are also tagged `main` are kept.
-name: Clean up images
+name: Images cleanup
 
 on:
   delete:
@@ -10,6 +10,7 @@ permissions:
 
 jobs:
   cleanup:
+    name: clean up
     if: github.event.ref_type == 'branch'
     runs-on: ubuntu-24.04
     steps:

.github/workflows/pr-rules.yml

@@ -1,7 +1,7 @@
 # Checks the pull request (see CONTRIBUTING.md), the PR becomes one commit in main when it is squash-merged:
 # - the title follows Conventional Commits, it becomes the commit message;
 # - the description links an issue (Closes #N or Refs #N).
-name: PR rules
+name: PR
 
 on:
   pull_request:
@@ -11,6 +11,7 @@ permissions: {}
 
 jobs:
   check:
+    name: title and issue link
     runs-on: ubuntu-24.04
     steps:
       - name: Title follows Conventional Commits

README.md

@@ -316,7 +316,7 @@ flowchart LR
 If you change headers or interfaces (messages, services) of a package, add the packages that depend on it to
 the overlay too. A new dependency in `package.xml` is not in the image: use a branch image for that.
 
-**Whole branch: branch image.** Push the branch, open *Actions → Build images → Run workflow*, choose the
+**Whole branch: branch image.** Push the branch, open *Actions → Images → Run workflow*, choose the
 branch. When the workflow is finished:
 ```bash
 ./rover.sh use my-branch     # back to the normal version: ./rover.sh use main