Add live bundle analyzer page to sx-docs

Demonstrates Phase 1 dep analysis in action: computes per-page component
bundles for all sx-docs pages using the deps.sx transitive closure
algorithm, showing needed vs total components with visual progress bars.

- New page at /plans/bundle-analyzer with Python data helper
- New components: ~bundle-analyzer-content, ~analyzer-stat, ~analyzer-row
- Linked from Phase 1 section and Plans nav
- Added sx/sx/ to tailwind content paths

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sx/sxc/pages/docs.sx

@@ -417,3 +417,16 @@
     "reader-macros" (~plan-reader-macros-content)
     "sx-activity" (~plan-sx-activity-content)
     :else (~plans-index-content)))
+
+(defpage bundle-analyzer
+  :path "/plans/bundle-analyzer"
+  :auth :public
+  :layout (:sx-section
+    :section "Plans"
+    :sub-label "Plans"
+    :sub-href "/plans/"
+    :sub-nav (~section-nav :items plans-nav-items :current "Bundle Analyzer")
+    :selected "Bundle Analyzer")
+  :data (bundle-analyzer-data)
+  :content (~bundle-analyzer-content
+    :pages pages :total-components total-components :total-macros total-macros))