Feat/761 signal bridge between backend and qml

[melaniereis]

Pull Request

Related issue(s): closes #761

Type of change

• feat: A new feature
• fix: A bug fix
• docs: Documentation only changes
• style: Formatting, missing semicolons, etc (no code change)
• refactor: Code change that neither fixes a bug nor adds a feature
• perf: A code change that improves performance
• test: Adding or updating tests
• ci: CI configuration changes
• chore: Maintenance tasks
• spike: Investigation / research

Summary

Implemented the communication bridge between the C++ backend logic and the QML layer to translate validated V2X CAN signals into real-time UI state changes for emergency alerts. Also fixed deployment/cache issues preventing the new binary from running on the target.

Key Implementation Details:

• Added HandleV2XEmergency to kuksa_feeder to decode the CAN frame (ID 0x500) and publish the priority level to the KUKSA Databroker (Vehicle.ADAS.V2X.EmergencyPriority).
• Registered the new handler in the Feeder's O(1) CAN dispatch table.
• Updated KuksaReader and CanReader to emit the emergencyAlertReceived signal upon detecting state changes.
• Connected the readers to VehicleData via AppController using Qt::QueuedConnection to guarantee thread safety.
• Updated ClusterScreen.qml with a Connections block to dynamically trigger the EmergencyAlert component based on priority levels (1 = Warning, 2 = High Priority) and added a 15-second HMI failsafe timeout.

How to test / Validation

1. Build the updated qt-app RPM via Bitbake (bitbake -c cleansstate qt-app && bitbake qt-app) and force install it on the Raspberry Pi 5 (dnf reinstall -y /tmp/qt-app-*.rpm).
2. Ensure the KUKSA Databroker is running and the system clock is synced (to prevent TLS cert errors).
3. Start the KUKSA Feeder with TLS enabled:

kuksa_feeder --tls --ca /etc/kuksa/ca.crt

4. Start the DrivaPi Dashboard (systemctl start drivapi-dashboard).
5. In a separate terminal on the target, inject the high-priority CAN frame:

cansend can1 500#02

Expected Output: The Feeder logs [Handler] Published Vehicle.ADAS.V2X.EmergencyPriority = 2 and the red "PULL OVER - EMERGENCY" banner immediately drops down in the UI.
6. Inject the clear command:

cansend can1 500#00

Expected Output: The UI banner retracts instantly.

Checklist

• I have run the project tests locally and they pass
• CI checks are green for this branch (or I will fix any failures)
• I have added or updated tests where applicable
• I have updated documentation (if applicable)
• I have added/updated any migration notes (if database or protocol changes)
• I have requested appropriate reviewers and added labels if needed
• This PR contains no secrets or sensitive data

Risks and backward compatibility

• CAN ID Strictness: The system expects the CAN ID to be sent as Hexadecimal 0x500 (1280 Decimal) from the STM32.
• VSS Datatype: The Feeder pushes the priority level as a Float (or matching type). Ensure the Databroker's vss.json schema matches this.

Related / dependent PRs

Depends on #760.

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Approval: Requires a minimum of 2 approvals.

Action: The feature branch MUST be deleted upon successful merge.

[github-actions]

✅ STM32 CI: firmware build succeeded

• Conclusion: success
• Run: https://github.com/SEAME-pt/Team04_DrivaPi/actions/runs/27942708733

[github-actions]

🔍 TSF Validation Results

Check	Status
trudag lint	✅ PASSED
trudag score	✅ PASSED
trudag publish	✅ PASSED

📋 Lint Output

WARNING: Unreviewed Item: HLTC-INT-PS3_DECODE_VALIDATE
WARNING: Unreviewed Item: LLTC-DC_MOTOR_UNIT
WARNING: Unreviewed Item: LLTC-SERVO_MOTOR_UNIT
WARNING: Unreviewed Item: LLTC-SPEED_SENSOR_UNIT
WARNING: Unreviewed Item: SWD-DC_MOTOR_DRIVER
WARNING: Unreviewed Item: SWD-SERVO_DRIVER
WARNING: Unreviewed Item: SWD-SPEED_CALC
WARNING: Suspect Link: SRD-ACT-MOTOR_DRIVE -> SWD-DC_MOTOR_DRIVER
WARNING: Suspect Link: SRD-ACT-SERVO_STEER -> SWD-SERVO_DRIVER
WARNING: Suspect Link: SRD-SENS-ENCODER_SPD 

📊 Traceability Graph

✅ Graph generated successfully

Download artifacts to view: TSF Validation Results

• Traceability graph: tsf-validation-artifacts/traceability_graph.svg
• Full TSF reports in artifact archive

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🧪 Unit Test Results

Overall Status: ✅ PASSED

• DC Motor Tests: PASSED (11/11)
• Servo Motor Tests: PASSED (5/5)
• Speed Sensor Tests: PASSED (16/16)
• Total: 32 tests

📊 Coverage

Coverage report available in artifacts.

🔍 Coverage Change Validation

• dc-motor: score=1.00 issues=[]
• servo-motor: score=1.00 issues=[]
• speed-sensor: score=1.00 issues=[]

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Full coverage reports available in workflow artifacts

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🔒 CodeQL (filtered SARIF summary)

Severity	Count
High/Critical (error)	0
Warnings	0
Notes	0

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🧪 Unit Test Results

Overall Status: ✅ PASSED

• DC Motor Tests: PASSED (11/11)
• Servo Motor Tests: PASSED (5/5)
• Speed Sensor Tests: PASSED (16/16)
• Total: 32 tests

📊 Coverage

Coverage report available in artifacts.

🔍 Coverage Change Validation

• dc-motor: score=1.00 issues=[]
• servo-motor: score=1.00 issues=[]
• speed-sensor: score=1.00 issues=[]

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Full coverage reports available in workflow artifacts

Run: https://github.com/SEAME-pt/Team04_DrivaPi/actions/runs/27942709949

[AfonsoMota-132]

approved