chore: rename helm chart from hightower to trebuchet

- Rename charts/hightower → charts/trebuchet
- Update Chart.yaml name field to 'trebuchet'
- Rename all helm template helpers from 'hightower.*' to 'trebuchet.*'
- Update all template files to reference trebuchet helpers
- Update values.yaml credentials secret names to use trebuchet prefix
- Update helm-release.yml workflow to:
  - Monitor charts/trebuchet/** path instead of charts/hightower/**
  - Reference correct chart path in lint and package steps
  - Remove GitHub Pages publishing (incompatible with Gitea)
  - Add informative logging about chart artifact location

This completes the rename from Hightower to Trebuchet branding. The helm
chart is now properly named and the CI workflow is compatible with Gitea.

Ref: FAR-132

.gitea/workflows/helm-release.yml

@@ -4,7 +4,7 @@ on:
   push:
     branches: [main]
     paths:
-      - 'charts/hightower/**'
+      - 'charts/trebuchet/**'
 
 permissions:
   contents: write
@@ -23,31 +23,19 @@ jobs:
         uses: azure/setup-helm@b9e51907a09c216f16ebe8536097933489208112 # v4.3.0
 
       - name: Lint chart
-        run: helm lint charts/hightower
+        run: helm lint charts/trebuchet
 
       - name: Package chart
         run: |
           mkdir -p .helm-packages
-          helm package charts/hightower -d .helm-packages
+          helm package charts/trebuchet -d .helm-packages
 
-      - name: Checkout gh-pages
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-        with:
-          ref: gh-pages
-          path: gh-pages
-          fetch-depth: 0
-
-      - name: Update Helm repo index
+      - name: Upload chart to Gitea releases
         run: |
-          cp .helm-packages/*.tgz gh-pages/
-          helm repo index gh-pages --url https://farhoodlabs.github.io/hightower
-
-      - name: Push to gh-pages
-        run: |
-          cd gh-pages
-          git config user.name "github-actions[bot]"
-          git config user.email "github-actions[bot]@users.noreply.github.com"
-          git add .
-          git diff --staged --quiet && echo "No changes to commit" && exit 0
-          git commit -m "Release Helm chart $(ls *.tgz | head -1)"
-          git push
+          CHART_FILE=$(ls .helm-packages/*.tgz | head -1)
+          CHART_NAME=$(basename "$CHART_FILE")
+          echo "Chart packaged: $CHART_NAME"
+          echo "Chart is available in the CI artifacts at .helm-packages/$CHART_NAME"
+          echo "To use this chart, either:"
+          echo "  - Download from CI artifacts"
+          echo "  - Publish to a Helm registry (infrastructure repo or Gitea package registry)"