Add contributors into the activity claim

.changeset/feat-contribution-weight.md

@@ -0,0 +1,36 @@
+---
+"@hypercerts-org/sdk-core": minor
+---
+
+**BREAKING CHANGE**: Update contribution structure to match lexicon beta.7+ inline contributor format.
+
+**Old API (lexicon beta.5-beta.6):**
+
+```typescript
+await repo.hypercerts.create({
+  contributions: [
+    {
+      contributors: ["did:plc:contrib1"],
+      role: "Developer",
+      description: "Led backend development",
+    },
+  ],
+});
+```
+
+**New API (lexicon beta.7+):**
+
+```typescript
+await repo.hypercerts.create({
+  contributions: [
+    {
+      contributors: ["did:plc:contrib1"],
+      contributionDetails: "Developer", // string | StrongRef | CreateContributionDetailsParams
+      weight: "0.75", // optional proportional weight
+    },
+  ],
+});
+```
+
+**Migration:** Replace `role` and `description` with `contributionDetails`. Optionally add `weight` for proportional
+attribution.