Add content-addressed components plan to sx-docs

7-phase plan: canonical serialization, CID computation, component
manifests, IPFS storage & resolution cascade, security model (purity
verification, content verification, eval limits, trust tiers),
wire format integration with prefetch system, and federated sharing
via AP component registry actors.

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

sx/sxc/pages/docs.sx

@@ -478,4 +478,5 @@
     "reader-macros" (~plan-reader-macros-content)
     "sx-activity" (~plan-sx-activity-content)
     "predictive-prefetch" (~plan-predictive-prefetch-content)
+    "content-addressed-components" (~plan-content-addressed-components-content)
     :else (~plans-index-content)))