ci: improve Bazel build verification and update .bazelignore

- Created BUILD.bazel files for all subprojects to enable recursive build verification.
- Updated root BUILD.bazel to track all project source files.
- Cleared .bazelignore of project directories to allow Bazel to scan them.
- Excluded files with colons from Bazel globs as they are invalid labels.

.bazelignore

@@ -1,23 +1,2 @@
-# Ignore all nested directories so Bazel doesn't scan submodules/workspaces
-figma-to-lit
-figma_lit_example
-lit-3d-piano
-lit-calculator
-lit-code-editor
-lit-draggable-dom
-lit-file-based-routing
-lit-force-graph
-lit-html-editor
-lit-html-table
-lit-modules
-lit-native
-lit-node-editor
-lit-sheet-music
-lit-starter-ts
-lit-vscode-extension
-lit-wmr
-vite-lit-capacitor
-vite-lit-element-starter
-vite-rxdb-lit
 node_modules
 dist