Add Content Addressing page under CEK Machine

Dedicated page documenting and demonstrating content-addressed
computation. How it works, why it matters, the path to IPFS.

Live demo: counter + name widget with CID generation, history,
and restore-from-CID input.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

sx/sx/geography/cek.sx

@@ -711,6 +711,63 @@
             (deref saved)))))))
 
 
+
+
+(defcomp ~geography/cek/cek-content-address-content ()
+  (~docs/page :title "Content-Addressed Computation"
+
+    (p :class "text-stone-500 text-sm italic mb-8"
+      "A computation is a value. A value has a hash. The hash is the address. "
+      "Same state, same address, forever.")
+
+    (~docs/section :title "The idea" :id "idea"
+      (p "Freeze a scope to SX. Hash the SX text. The hash is a content identifier (CID). "
+         "Store the frozen SX keyed by CID. Later, look up the CID, thaw, resume.")
+      (p "The critical property: "
+         (strong "same state always produces the same CID") ". "
+         "Two machines freezing identical signal values get identical CIDs. "
+         "The address IS the content."))
+
+    (~docs/section :title "How it works" :id "how"
+      (~docs/code :code (highlight
+        ";; Freeze a scope \u2192 hash \u2192 CID\n(freeze-to-cid \"widget\")\n;; => \"d9eea67b\"\n\n;; The frozen SX is stored by CID\n(content-get \"d9eea67b\")\n;; => {:name \"widget\" :signals {:count 42 :name \"hello\"}}\n\n;; Thaw from CID \u2192 signals restored\n(thaw-from-cid \"d9eea67b\")\n;; Signals reset to frozen values"
+        "lisp"))
+      (p "The hash is djb2 for now \u2014 deterministic and fast. "
+         "Real deployment uses SHA-256 / multihash for IPFS compatibility."))
+
+    (~docs/section :title "Why it matters" :id "why"
+      (ul :class "list-disc pl-6 mb-4 space-y-2 text-stone-600"
+        (li (strong "Sharing") " \u2014 send a CID, not a blob. "
+            "The receiver looks up the CID and gets the exact state.")
+        (li (strong "Deduplication") " \u2014 same state = same CID. "
+            "Store once, reference many times.")
+        (li (strong "Verification") " \u2014 re-freeze, compare CIDs. "
+            "If they match, the state is identical. No diffing needed.")
+        (li (strong "History") " \u2014 each CID is a snapshot. "
+            "A sequence of CIDs is a complete undo history.")
+        (li (strong "Distribution") " \u2014 CIDs on IPFS are global. "
+            "Pin a widget state, anyone can thaw it. "
+            "No server, no API, no account.")))
+
+    (~docs/section :title "Live demo" :id "demo"
+      (p "Change the counter and name. Click " (strong "Content-address") " to freeze and hash. "
+         "The CID appears below. Change the values, then click any CID in the history "
+         "or paste one into the input to restore.")
+      (~geography/cek/content-address-demo))
+
+    (~docs/section :title "The path to IPFS" :id "ipfs"
+      (p "The content store is currently in-memory. The next steps:")
+      (ul :class "list-disc pl-6 mb-4 space-y-1 text-stone-600"
+        (li "Replace djb2 with SHA-256 (browser SubtleCrypto)")
+        (li "Wrap in multihash + CIDv1 format")
+        (li "Store to IPFS via the Art DAG L2 registry")
+        (li "Pin CIDs attributed to " (code "sx-web.org"))
+        (li "Anyone can pin, fork, extend"))
+      (p "The frozen SX is the content. The CID is the address. "
+         "IPFS is the network. The widget state becomes a permanent, "
+         "verifiable, shareable artifact \u2014 not trapped in a database, "
+         "not behind an API, not owned by anyone."))))
+
 ;; ---------------------------------------------------------------------------
 ;; Demo page content
 ;; ---------------------------------------------------------------------------

sx/sx/nav-data.sx

@@ -176,7 +176,9 @@
   (dict :label "Demo" :href "/sx/(geography.(cek.demo))"
         :summary "Live islands evaluated by the CEK machine. Counter, computed chains, reactive attributes — all through explicit continuation frames.")
   (dict :label "Freeze / Thaw" :href "/sx/(geography.(cek.freeze))"
-        :summary "Serialize a CEK state to s-expressions. Ship it, store it, content-address it. Thaw and resume anywhere.")))
+        :summary "Serialize a CEK state to s-expressions. Ship it, store it, content-address it. Thaw and resume anywhere.")
+  (dict :label "Content Addressing" :href "/sx/(geography.(cek.content))"
+        :summary "Hash frozen state to a CID. Same state = same address. Store, share, verify, reproduce.")))
 
 (define plans-nav-items (list
   (dict :label "Status" :href "/sx/(etc.(plan.status))"

sx/sx/page-functions.sx

@@ -67,6 +67,7 @@
       (case slug
         "demo" '(~geography/cek/cek-demo-content)
         "freeze" '(~geography/cek/cek-freeze-content)
+        "content" '(~geography/cek/cek-content-address-content)
         :else '(~geography/cek/cek-content)))))
 
 (define provide