feat: add Dev HUD & 15 Obsidian callouts; more collection filters

Dev tools
- Add HBX Dev HUD (floating button + panel) with live log viewer
- Add get-build-id helper to dedupe logs per build (during `hugo server` refreshes)

Callouts
- Implement Obsidian-compatible callouts (15+ types) with shared renderer
- Add i18n title translations (en, es, fr) for all callout types
- Deprecate `callout` shortcode with suppressible warning; keep working
- Migrate starters to Markdown callouts (>[!TYPE]) and update docs

Logging
- Centralize logging in partial `functions/logger` with info/warn/error levels
- Use fmt.Warnidf for suppressible warnings (consistent IDs)
- Only show info in Dev HUD/JSON (no longer use warnf for info logging); warn/error still printed in CLI
- Include source metadata and build ID on each entry

Blocks – Collection
- Add support for `content.filters.kinds`
- Add `content.filters.tags` (array) alongside existing `filters.tag` (string)

Build/Tailwind/JS
- Fix missing Tailwind v4 styles in Hugo render: include preact-built assets, extract classes from JSX/TSX to `@sources`
- Load Preact client per block, publish source maps in dev; on-demand Alpine

CI
- Re-implement fast fails with panicOnWarning now that info logging as warnf removed
- Fix package splitter change detection: strip trailing slashes; collapse paths to starter roots

Starters/Docs
- Restructure courses under `courses/hugo-blox/`
- Update menus and landing pages
- Replace deprecated callout usage in content and docs
- Replace missing hero icon `download` with `arrow-down-tray` in academic-cv guide

Icons
- Improve icon resolver: default pack inference, better fallback, and precise missing-icon warnings (with page ref)

scripts/view-starter-dev.sh

@@ -106,6 +106,7 @@ HUGO_ARGS=(
 
 if [ "$DEBUG_MODE" = true ]; then
     HUGO_ARGS+=(
+        --panicOnWarning
         --logLevel debug
         --templateMetrics
         --templateMetricsHints