Fix two HIGH-severity tutorial bugs (CMake example + rviz image publisher)

[mmmarinho]

This PR fixes the two HIGH-severity issues found during a full static + manual audit of the tutorial.

1. CMake example built a source file that does not exist

cmake_tutorial_workspace/src/cpp_cmake_example_qpoases_lib/CMakeLists.txt
declared project(test_proxsuite) and add_executable(${PROJECT_NAME} ${PROJECT_NAME}.cpp), i.e. it
tried to build test_proxsuite.cpp — which does not exist. The only C++ source present (and the
one shown to the reader in the test_qpoases.cpp tab) is src/test_qpoases.cpp.

It also had FIND_PACKAGE(Eigen3 REQUIRED) even though the example never uses Eigen.

A reader following Install a CMake package → Example: include and link the qpOASES in your project
(docs/source/cmake/cmake_packages_without_sudo.rst) would have failed at the build step.

Fix:

• project(test_proxsuite) → project(test_qpoases)
• source path ${PROJECT_NAME}.cpp → src/${PROJECT_NAME}.cpp
• removed the two Eigen lines
• in the lesson: dropped the now-inaccurate "Eigen" from the warning, corrected the
  :emphasize-lines: offset (17 → 15, since two lines were removed above it), and fixed the download
  label test_dqrobotics.cpp → test_qpoases.cpp so it matches the tab title and the actual file.

2. transformations/rviz.rst: "Publish sample images" used a non-existent executable

The tab Terminal 1: Publish sample images instructed
ros2 run rqt_image_view image_publisher. rqt_image_view is a visualiser, not a publisher —
there is no image_publisher executable in it, so the command fails. The following sentence even says
"We will use the visualiser, not the publisher", confirming a publisher was intended.

Fix: use the real ROS2 image_publisher package (ships with ros-desktop, so readers have it).
On Jazzy its executable is image_publisher_node; it takes an image path and publishes on image_raw,
so the topic is remapped to /images to match the visualiser:

ros2 run image_publisher image_publisher_node /path/to/lenna.png \
    --ros-args -r image_raw:=/images

Also corrected the second tab title from "Run the bridge" to "Run the visualiser".

3. Tracking

Added ISSUES.md at the repo root with the full audit. Both HIGH items are marked [x] fixed; the
remaining MEDIUM (dead pages, stale Humble/Foxy links) and LOW items are listed with severity,
file:line, and a suggested fix so they can be addressed in a follow-up PR.

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Created by an AI agent (OpenHands) on behalf of the user.

[mmmarinho]

👍