feat(rules page): rebuild directory rules page with vendored lists (#1147)

* feat(rules page): rebuild directory rules page with vendored lists

Mirror per-directory JSON from lists into src/data/5chan-directories, rework /rules layout to match 4chan (sidebar nav, category boxes, P2P load), and keep spoiler markup visible in rule text via parseSpoilers.

* fix(rules): keep directory defaults cache atomic

* fix(rules): derive defaults from shared directory refresh

* fix(rules): address directory refresh edge cases

src/data/5chan-directories/5chan-sp-directory.json

@@ -0,0 +1,13 @@
+{
+  "description": "Boards competing to host the /sp/ directory on 5chan. The highest-scoring board resolves the directory code; if it goes offline, 5chan rotates to the next-highest. Anyone can open a PR on this file to add their board.\n\nhttps://github.com/bitsocialnet/lists/blob/master/5chan-directories/5chan-sp-directory.json",
+  "createdAt": 1779182014,
+  "updatedAt": 1779182014,
+  "boards": [
+    {
+      "address": "sports-posting.bso",
+      "publicKey": "12D3KooWGJA6zN3Q63FtSgwNhtfA26Skdzdxz5X7A9PFfE4FBMGE",
+      "addedAt": 1779182014,
+      "owner": "plebeius.bso"
+    }
+  ]
+}