Align project paths with timeline model

frontend/src/arthur/domain/leaf.cljs

@@ -19,13 +19,9 @@
       clip/<cid>/timeline/<tid>/channel/<nid>/<prop>
       clip/<cid>/timeline/<tid>/measured/<nid>      the channels a re-freeze owns
 
-  WHY NODES SIT UNDER A TIMELINE. They did not until the clip and the timeline came
-  apart, and the flat `clip/<cid>/node/<nid>` was the persistence half of the same
-  conflation: it could only ever address the nodes of the one bag a clip had. A
-  library symbol is a timeline, an instance references one, and both need their
-  nodes addressed — so the timeline id is a segment, the root is `main`, and a
-  symbol's nodes are reachable by the same path shape as the clip's own. Adding it
-  later would have meant rewriting every stored path.
+  WHY NODES SIT UNDER A TIMELINE. A clip holds a library of timelines. Its root
+  and each symbol have their own nodes, so the timeline id is a path segment.
+  The root is `main`, and a symbol's nodes use the same path shape.
 
   `:frames` MOVED OFF `timing` onto the timeline. A timeline is a frame space and a
   clip is a rate, so `timing` holds `:fps` alone. Both used to be in one leaf, which

frontend/src/arthur/domain/project.cljs

@@ -53,7 +53,8 @@
   round-trip a clip through `JSON.parse(JSON.stringify(...))` and be running the
   same conversion the network runs, rather than a CLJS-shaped rehearsal of it. The
   one thing a keywordising `js->clj` would quietly break is the leaf paths —
-  `:clip/c1/node/mouth` is a keyword whose `name` is \"c1/node/mouth\", so the
+  `:clip/c1/timeline/main/node/mouth` is a keyword whose `name` is
+  \"c1/timeline/main/node/mouth\", so the
   \"clip/\" would be lost on the way back in.
 
   Refuses a document `domain/leaf` calls unaddressable, which is where a hand-made

frontend/src/arthur/fx/http.cljs

@@ -4,7 +4,8 @@
   Everything here returns a promise of a PARSED JS VALUE, not of CLJS data, and
   that is deliberate: a leaf is transit, and `domain/project` reads it straight out
   of the response object. A keywordising `js->clj` on the way past would turn the
-  leaf path \"clip/c1/node/mouth\" into a keyword whose name is \"c1/node/mouth\",
+  leaf path \"clip/c1/timeline/main/node/mouth\" into a keyword whose name is
+  \"c1/timeline/main/node/mouth\",
   losing the prefix — a corruption that only shows up on the way back in.
 
   CSRF IS NOT EXEMPTED. The page renders `{% csrf_token %}`, so Django sets its

frontend/test/arthur/domain/feature_test.cljs

@@ -1,5 +1,6 @@
 (ns arthur.domain.feature-test
   (:require [cljs.test :refer [deftest is]]
+            [arthur.domain.clip :as clip]
             [arthur.domain.feature :as feature]
             [arthur.domain.params :as params]))
 
@@ -17,11 +18,14 @@
                                        [id {:id id :kind :eye-pair
                                             :subject (nth people i)
                                             :members ids :params {}}])) members))
-     :nodes {}}))
+     :timelines {:main {:id :main :frames 1 :nodes {}}}}))
+
+(defn- problems [c]
+  (feature/problems c (clip/nodes c)))
 
 (deftest five-people-can-have-nine-identified-eyes
   (let [scene (nine-eyes)]
-    (is (empty? (feature/problems scene)))
+    (is (empty? (problems scene)))
     (is (= [:eye-8] (get-in scene [:groups :pair-4 :members])))
     (is (= :person-4 (get-in scene [:features :eye-8 :subject])))))
 
@@ -41,11 +45,11 @@
           unpaired (feature/remove-from-pair scene :eye-0)]
       (is (= before (feature/effective-params unpaired :eye-0)))
       (is (= [:eye-1] (get-in unpaired [:groups :pair-0 :members])))
-      (is (empty? (feature/problems unpaired))))))
+      (is (empty? (problems unpaired))))))
 
 (deftest a-pair-cannot-cross-subjects-or-own-an-eye-twice
   (let [scene (nine-eyes)]
-    (is (seq (feature/problems
+    (is (seq (problems
               (assoc-in scene [:groups :pair-0 :members] [:eye-0 :eye-2]))))
-    (is (seq (feature/problems
+    (is (seq (problems
               (assoc-in scene [:groups :pair-1 :members] [:eye-0 :eye-3]))))))