fix(desktop): keep createdBy=learn through the starmap share code

The share-code codec encodes createdBy through a fixed table that only
knew none/agent/user, so idxOf returned 0 for 'learn' and a learned
skill round-tripped as createdBy: null. The 2-bit field has a free slot,
so 'learn' now occupies it, and metaBadges labels agent- and
learn-created skills alike as 'learned' — matching the Python side,
where both values count as learning signals.

Review finding: learn nodes lost createdBy in share-code round-trip.

apps/desktop/src/app/starmap/share-code.test.ts

@@ -29,7 +29,7 @@ function sampleGraph(): StarmapGraph {
       },
       {
         category: 'devops',
-        createdBy: null,
+        createdBy: 'learn',
         id: 'skill-b',
         kind: 'skill',
         label: 'skill-b',

apps/desktop/src/app/starmap/share-code.ts

@@ -20,7 +20,7 @@ const trim = (s: string): string => (s.length > MAX_LABEL ? s.slice(0, MAX_LABEL
 const KINDS = ['skill', 'memory'] as const
 const STATES = ['active', 'archived', 'disabled', 'draft'] as const
 const MEM_SOURCES = ['none', 'memory', 'profile'] as const
-const CREATED_BY = ['none', 'agent', 'user'] as const
+const CREATED_BY = ['none', 'agent', 'user', 'learn'] as const
 
 const REC_BITS = 12 // time position resolution: 1/4096 of the span — sub-pixel here.
 const REC_MAX = (1 << REC_BITS) - 1

apps/desktop/src/app/starmap/text.ts

@@ -23,7 +23,7 @@ export function metaBadges(n: StarmapNode): string[] {
   } else {
     out.push(n.category)
 
-    if (n.createdBy === 'agent') {
+    if (n.createdBy === 'agent' || n.createdBy === 'learn') {
       out.push('learned')
     }