Add external dependencies CI/CD pipelines with SBOM generation

- Create external-dependencies directory structure with per-package pipelines
- Add DEPENDENCIES-INVENTORY.md with comprehensive dependency tracking
- Create ubuntu-26.04-build-container base image with all dependencies
- Add per-package Jenkinsfiles: log4qt, grantlee, googletest, postgresql, qt6-framework, kdreports
- Add SBOM generation script (generate-sbom.sh) for CycloneDX, SLSA v1.0, and license reports
- Integrate SBOM generation into all Jenkins pipelines
- Add external-dependencies/README.md with usage and security documentation
- Exclude proprietary license files (rti_license.dat) from git tracking

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Entire-Checkpoint: 01M6KNFNMSPW4SY4J4SQTTPVBP

external-dependencies/kdreports/README.md

@@ -0,0 +1,43 @@
+# KDReports
+
+KDReports installation pipeline for Qt6 support.
+
+## Version
+
+- **KDReports:** 2.3.0 (kdreports-2.3.0 tag)
+- **Repository:** https://github.com/KDAB/KDReports
+- **License:** GPL/Commercial
+
+## Installation
+
+```bash
+git clone --depth 1 --branch kdreports-2.3.0 https://github.com/KDAB/KDReports.git /tmp/KDReports
+cd /tmp/KDReports
+mkdir build && cd build
+cmake -DCMAKE_BUILD_TYPE=Release \
+      -DCMAKE_INSTALL_PREFIX=/usr/local \
+      -DCMAKE_PREFIX_PATH=/opt/Qt/6.10.2/gcc_64 \
+      -DKDReports_QT6=ON ..
+cmake --build . -j$(nproc)
+cmake --install .
+```
+
+## Header Alias
+
+For legacy `<KDReports/...>` includes:
+
+```bash
+ln -sfn /usr/local/include/KDReports-qt6 /usr/local/include/KDReports
+```
+
+## Verification
+
+```bash
+pkg-config --modversion KDReports-qt6
+```
+
+## SBOM
+
+- `sbom/kdreports-2.3.0-sbom.json`
+- `sbom/kdreports-2.3.0-provenance.json`
+- `sbom/kdreports-2.3.0-licenses.md`