Add plans audit: status overview + fragment protocol, glue decoupling, social sharing pages

Audit all plan files and create documentation pages for what remains:
- Status overview with green/amber/stone badges for all 15 plans
- Fragment Protocol: what exists (GET), what remains (POST sexp, structured response)
- Glue Decoupling: 25+ cross-app imports to eliminate via glue service layer
- Social Sharing: 6-phase OAuth-based sharing to major platforms

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

sx/sx/nav-data.sx

@@ -109,10 +109,18 @@
   (dict :label "Routing Analyzer" :href "/isomorphism/routing-analyzer")))
 
 (define plans-nav-items (list
+  (dict :label "Status" :href "/plans/status"
+        :summary "Audit of all plans — what's done, what's in progress, and what remains.")
   (dict :label "Reader Macros" :href "/plans/reader-macros"
         :summary "Extensible parse-time transformations via # dispatch — datum comments, raw strings, and quote shorthand.")
   (dict :label "SX-Activity" :href "/plans/sx-activity"
-        :summary "A new web built on SX — executable content, shared components, parsers, and logic on IPFS, provenance on Bitcoin, all running within your own security context.")))
+        :summary "A new web built on SX — executable content, shared components, parsers, and logic on IPFS, provenance on Bitcoin, all running within your own security context.")
+  (dict :label "Fragment Protocol" :href "/plans/fragment-protocol"
+        :summary "Structured sexp request/response for cross-service component transfer.")
+  (dict :label "Glue Decoupling" :href "/plans/glue-decoupling"
+        :summary "Eliminate all cross-app model imports via glue service layer.")
+  (dict :label "Social Sharing" :href "/plans/social-sharing"
+        :summary "OAuth-based sharing to Facebook, Instagram, Threads, Twitter/X, LinkedIn, and Mastodon.")))
 
 (define bootstrappers-nav-items (list
   (dict :label "Overview" :href "/bootstrappers/")