docs: clarify CalVer release policy

.agents/skills/changeset-changelog/evals/evals.json

@@ -10,7 +10,7 @@
     {
       "id": 2,
       "prompt": "Add release notes for this new CLI option before we merge.",
-      "expected_output": "The assistant should add a changeset fragment for @jmfederico/pi-web with an appropriate minor or patch bump depending on the option, and keep the text user-facing.",
+      "expected_output": "The assistant should add a changeset fragment for @jmfederico/pi-web using patch for a backward-compatible CLI option, reserve major only for explicit user-requested breaking releases, avoid minor because pi-web uses the semver minor slot for YYYYMM, and keep the text user-facing.",
       "files": []
     },
     {
@@ -18,6 +18,12 @@
       "prompt": "Can we update CHANGELOG.md now with the fix I just made?",
       "expected_output": "The assistant should explain that normal development should use a .changeset fragment instead of manually editing CHANGELOG.md, then offer to create that fragment.",
       "files": []
+    },
+    {
+      "id": 4,
+      "prompt": "Please write a changeset for this config migration; older config files may not load after it lands.",
+      "expected_output": "The assistant should identify the possible breaking change and ask the user to confirm whether they explicitly want a breaking major release or want the change made backward-compatible before writing a major changeset.",
+      "files": []
     }
   ]
 }