CI: Fix issues, centralize config, improve caching

.dockerignore

@@ -1,15 +1,81 @@
-# Ignore Git repository files
+# ==============================================================================
+# Docker Build Context Exclusions
+# ==============================================================================
+
+# Git
 .git
 .gitignore
 .gitattributes
+.gitmodules
+.mailmap
 
-# Ignore node_modules or other build artifacts
-node_modules
-build
-
-# Ignore Docker-related files
-Dockerfile*
-docker-compose.yml
+# GitHub (except build-config.json needed by Dockerfile)
+.github/
+!.github/build-config.json
 
+# Documentation (not needed for build)
+docs/
 README.md
+CHANGELOG.md
+LICENSE-*
+
+# Build artifacts
+build/
+cmake-build-*/
+out/
+cpm_modules/
+compile_commands.json
 CMakeLists.txt.user*
+CMakeUserPresets.json
+
+# IDEs & Editors
+.idea/
+.vscode/
+.qtcreator/
+.fleet/
+.vs/
+.settings/
+*.swp
+*~
+tags
+
+# Node.js (docs build)
+node_modules/
+package-lock.json
+
+# Python
+*.pyc
+__pycache__/
+.ruff_cache/
+
+# Local development
+.claude/
+.cache/
+sessions/
+CLAUDE.md
+AGENTS.md
+GEMINI.md
+
+# Platform artifacts
+.DS_Store
+*.exe
+*.dll
+*.so
+*.dylib
+*.app
+*.dmg
+*.deb
+*.rpm
+*.AppImage
+*.apk
+*.aab
+*.ipa
+
+# Test artifacts
+*.gcov
+*.gcda
+*.gcno
+*.coverage
+
+# Vagrant
+.vagrant/

.github/CITATION.cff

@@ -0,0 +1,25 @@
+cff-version: 1.2.0
+title: QGroundControl
+message: >-
+  If you use QGroundControl in your research, please cite it using
+  the metadata from this file.
+type: software
+authors:
+  - name: QGroundControl Development Team
+    website: https://qgroundcontrol.com
+repository-code: https://github.com/mavlink/qgroundcontrol
+url: https://qgroundcontrol.com
+abstract: >-
+  QGroundControl is an intuitive and powerful ground control station
+  for UAVs. It provides full flight control and mission planning for
+  any MAVLink-enabled drone, including PX4 and ArduPilot vehicles.
+keywords:
+  - ground-control-station
+  - uav
+  - drone
+  - mavlink
+  - px4
+  - ardupilot
+  - flight-planning
+  - telemetry
+license: Apache-2.0 AND GPL-3.0-only

.github/CODEOWNERS

@@ -0,0 +1,15 @@
+# CODEOWNERS - Auto-assign reviewers to pull requests
+# https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners
+
+# Default owners for everything
+# * @mavlink/qgc-maintainers
+
+# Documentation
+/docs/ @hamishwillee
+
+# QML/UI
+*.qml @DonLakeFlyer
+
+# Build system
+CMakeLists.txt @HTRamsey
+/cmake/ @HTRamsey

.github/CONTRIBUTING.md

@@ -21,7 +21,7 @@ Before you begin, please:
 
 1. Read the [Developer Guide](https://dev.qgroundcontrol.com/en/)
 2. Review the [Build Instructions](https://dev.qgroundcontrol.com/en/getting_started/)
-3. Familiarize yourself with the [Architecture](copilot-instructions.md)
+3. Familiarize yourself with the [Architecture Patterns](#architecture-patterns) in this guide
 
 ### Development Environment
 
@@ -59,6 +59,10 @@ Feature requests are welcome! Please:
 3. Consider implementation complexity
 4. Be prepared to contribute code if possible
 
+### Contributing Translations
+
+QGroundControl uses [Crowdin](https://crowdin.com/project/qgroundcontrol) for community translations. See [tools/translations/README.md](../tools/translations/README.md) for details on how translations are managed.
+
 ### Contributing Code
 
 1. **Fork the repository**
@@ -96,6 +100,8 @@ Feature requests are welcome! Please:
 
 ## Coding Standards
 
+For the complete coding style guide with examples, see [CODING_STYLE.md](../CODING_STYLE.md).
+
 ### C++ Guidelines
 
 - **Standard**: C++20
@@ -126,7 +132,8 @@ Feature requests are welcome! Please:
 
 - **Code formatting**:
   - Run `clang-format` before committing
-  - Follow `.clang-format` in the repository
+  - Follow `.clang-format`, `.clang-tidy`, `.editorconfig` in repo root
+  - See `CodingStyle.h`, `CodingStyle.cc`, `CodingStyle.qml` for examples
   - 4 spaces for indentation (no tabs)
 
 ### QML Guidelines
@@ -151,36 +158,66 @@ qCCritical(MyComponentLog) << "Critical error";
 
 ### Architecture Patterns
 
-#### Fact System (Required for Parameters)
+#### Fact System (Most Important!)
 
-Always use the Fact System for vehicle parameters:
+The Fact System handles ALL vehicle parameters. Never create custom parameter storage.
 
 ```cpp
+// Access parameters (always null-check!)
 Fact* param = vehicle->parameterManager()->getParameter(-1, "PARAM_NAME");
-if (param) {
-    param->setCookedValue(newValue);  // For display values
-    // param->setRawValue(newValue);  // For MAVLink values
+if (param && param->validate(newValue, false).isEmpty()) {
+    param->setCookedValue(newValue);  // Use cookedValue for UI (with units)
+    // param->rawValue() for MAVLink/storage
 }
 ```
 
-#### Multi-Vehicle Awareness
+**Key classes:**
+- `Fact` - Single parameter with validation, units, metadata
+- `FactGroup` - Hierarchical container (handles MAVLink via `handleMessage()`)
+- `FactMetaData` - JSON-based metadata (min/max, enums, descriptions)
+
+**Rules:**
+- Wait for `parametersReady` signal before accessing
+- Use `cookedValue` (display) vs `rawValue` (storage)
+- Metadata in `*.FactMetaData.json` files
 
-Always check for null vehicles:
+#### Multi-Vehicle Support
+
+Always null-check the active vehicle:
 
 ```cpp
 Vehicle* vehicle = MultiVehicleManager::instance()->activeVehicle();
-if (vehicle) {
-    // Use vehicle
-}
+if (!vehicle) return;
+
+// Other managers
+SettingsManager::instance()->appSettings()->...
+LinkManager::instance()->...
 ```
 
 #### Firmware Plugin System
 
-Use FirmwarePlugin for firmware-specific behavior instead of hardcoding:
+Use FirmwarePlugin for firmware-specific behavior:
 
 ```cpp
-vehicle->firmwarePlugin()->isCapable(capability);
+// FirmwarePlugin - Firmware behavior (flight modes, capabilities)
 vehicle->firmwarePlugin()->flightModes();
+vehicle->firmwarePlugin()->isCapable(capability);
+
+// AutoPilotPlugin - Vehicle setup UI
+// VehicleComponent - Individual setup items (Radio, Sensors, Safety)
+```
+
+#### QML/C++ Integration
+
+```cpp
+Q_OBJECT
+QML_ELEMENT           // Creatable in QML
+QML_SINGLETON         // Singleton
+QML_UNCREATABLE("")   // C++-only
+
+Q_PROPERTY(Type name READ getter WRITE setter NOTIFY signal)
+Q_INVOKABLE void method();
+Q_ENUM(EnumType)
 ```
 
 ---
@@ -308,7 +345,6 @@ For more details, see [COPYING.md](COPYING.md).
 
 - **User Manual**: https://docs.qgroundcontrol.com/en/
 - **Developer Guide**: https://dev.qgroundcontrol.com/en/
-- **API Documentation**: In-code documentation and `copilot-instructions.md`
 - **Support Guide**: For help and community resources, see [SUPPORT.md](SUPPORT.md)
 - **Discussion Forum**: https://discuss.px4.io/c/qgroundcontrol
 - **Discord**: https://discord.gg/dronecode

.github/DISCUSSION_TEMPLATE/polls.yml

@@ -0,0 +1,18 @@
+title: "[Poll] "
+labels: []
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Create a poll to gather community feedback. After creating this discussion, use the poll button in the editor to add your poll options.
+
+  - type: textarea
+    id: context
+    attributes:
+      label: Poll Context
+      description: Provide background information for your poll
+      placeholder: |
+        What decision or feedback are you seeking?
+        Why is this important to the community?
+    validations:
+      required: true

.github/DISCUSSION_TEMPLATE/q-a.yml

@@ -0,0 +1,86 @@
+title: "[Q&A] "
+labels: []
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for your question! Please check the following resources first:
+        - [User Guide](https://docs.qgroundcontrol.com/)
+        - [Developer Guide](https://dev.qgroundcontrol.com/)
+        - [Existing discussions](https://github.com/mavlink/qgroundcontrol/discussions)
+
+  - type: dropdown
+    id: category
+    attributes:
+      label: Question Category
+      description: What area does your question relate to?
+      options:
+        - Setup / Installation
+        - Vehicle Connection
+        - Flight Planning / Missions
+        - Video Streaming
+        - Telemetry / Parameters
+        - Custom Builds
+        - Development / Building from Source
+        - Other
+    validations:
+      required: true
+
+  - type: dropdown
+    id: platform
+    attributes:
+      label: Platform
+      description: What platform are you using?
+      options:
+        - Windows
+        - macOS
+        - Linux
+        - Android
+        - iOS
+        - Multiple / N/A
+    validations:
+      required: true
+
+  - type: dropdown
+    id: firmware
+    attributes:
+      label: Flight Stack
+      description: What firmware are you using?
+      options:
+        - PX4
+        - ArduPilot
+        - Both / Either
+        - N/A
+    validations:
+      required: false
+
+  - type: input
+    id: version
+    attributes:
+      label: QGC Version
+      description: Which version of QGroundControl?
+      placeholder: "e.g., 4.4.0, daily build"
+    validations:
+      required: false
+
+  - type: textarea
+    id: question
+    attributes:
+      label: Question
+      description: Describe your question in detail
+      placeholder: |
+        What I'm trying to do:
+
+        What I've tried:
+
+        What I expected vs what happened:
+    validations:
+      required: true
+
+  - type: textarea
+    id: context
+    attributes:
+      label: Additional Context
+      description: Any additional information, screenshots, or logs
+    validations:
+      required: false

.github/FUNDING.yml

@@ -0,0 +1,4 @@
+# Funding links displayed on repository sidebar
+# https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/displaying-a-sponsor-button-in-your-repository
+
+custom: ['https://www.dronecode.org']