fix(docker): update Dockerfile and CI for monorepo workspace structure

Dockerfile:
- Add shared-builder stage that produces @trek/shared dist before
  client and server stages need it
- Each build stage carries root package.json + package-lock.json so npm
  can resolve @trek/shared as a workspace dependency
- Production stage installs via workspace context (npm ci --workspace=server
  --omit=dev) so node_modules/@trek/shared symlinks to shared/dist correctly
- Copy server/tsconfig.json into the image so tsconfig-paths/register can
  find the MCP SDK path aliases at runtime
- CMD cds into /app/server before starting node so tsconfig-paths baseUrl
  resolves and ../node_modules points to /app/node_modules
- Remove mkdir for /app/server (now a real dir); keep symlinks for uploads/data

docker.yml version-bump:
- Replace manual per-workspace cd+npm-version calls with single:
  npm version --workspaces --include-workspace-root --no-git-tag-version
  (mirrors the version:* scripts in root package.json)
- git add now references root package-lock.json; adds shared/package.json

.dockerignore: add shared/dist
package.json: fix version:prerelease preid (alpha → pre)

.github/workflows/docker.yml

@@ -102,16 +102,15 @@ jobs:
           echo "VERSION=$NEW_VERSION" >> $GITHUB_OUTPUT
           echo "$STABLE → $NEW_VERSION ($BUMP)"
 
-          # Update package.json files and Helm chart
-          cd server && npm version "$NEW_VERSION" --no-git-tag-version && cd ..
-          cd client && npm version "$NEW_VERSION" --no-git-tag-version && cd ..
+          # Update all workspace + root package.json files and the root lockfile in one shot
+          npm version "$NEW_VERSION" --workspaces --include-workspace-root --no-git-tag-version
           sed -i "s/^version: .*/version: $NEW_VERSION/" charts/trek/Chart.yaml
           sed -i "s/^appVersion: .*/appVersion: \"$NEW_VERSION\"/" charts/trek/Chart.yaml
 
           # Commit and tag
           git config user.name "github-actions[bot]"
           git config user.email "github-actions[bot]@users.noreply.github.com"
-          git add server/package.json server/package-lock.json client/package.json client/package-lock.json charts/trek/Chart.yaml
+          git add package.json package-lock.json server/package.json client/package.json shared/package.json charts/trek/Chart.yaml
           git commit -m "chore: bump version to $NEW_VERSION [skip ci]"
           git tag "v$NEW_VERSION"
           git push origin main --follow-tags