tests: add test coverage with sonar

[tarruk]

Description

What this PR adds

A self-contained coverage pipeline for our repo:

• coverage/full_coverage.py – drives the whole flow, ending with an
  LCOV report that SonarQube understands.
• updated sonar-project.properties – aligns sonar.sources,
  sonar.tests, and the coverage path with the script.

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🛠️ How it works — step by step

#	Stage	What happens
1	Read config	Parses sonar-project.properties and uses the exact same folders declared in sonar.sources.
2	Safety check	Prints a warning if it finds modules/*/lib folders not listed in sonar.sources (they would otherwise be ignored by SonarQube).
3	Per-module tests	Runs flutter test --coverage inside each module that has a test/ folder. Generates one lcov.info per module.
4	Path normalisation	Rewrites every SF: line so it starts with either app/lib/… or modules/<module>/lib/… — this guarantees SonarQube can map the file.
5	Merge + zero-coverage	Combines all module reports and adds 0 % blocks for every Dart file that still has no tests, giving us a full-project view.
6	Validation & upload	Verifies that all paths match sonar.sources, then launches sonar-scanner to upload the final report.

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Usage

# Interactive (asks before running sonar-scanner)
python3 coverage/full_coverage.py

# CI / non-interactive (always runs sonar-scanner)
python3 coverage/full_coverage.py --ci

# Dry-run (show commands, don’t execute anything)
python3 coverage/full_coverage.py --dry-run
@rs-gpt-review Describe the changes in this PR. Recommend improvements (including code improvements), possible memory leaks, and best practices.

[ManuViola77]

💜 🥳 🚀

[amaury901130]

I hitnk you are missing the python instalation

• name: Install Python dependencies
  run: |
  python3 -m pip install --upgrade pip
  # Add any required pip install commands here, e.g.:
  # pip install somepackage

[tarruk]

@amaury901130
Nice catch! Just a heads-up: the ubuntu-latest runners already include Python 3 by default, so we don’t need an extra installation step. Since we’re not using any third-party Python dependencies, there’s nothing else to install right now.