feat(FN-1216): rename extension tools to fn_* across CLI and docs

- Rename all pi extension tool registrations from kb_* to fn_* across task, mission, and agent tool families
- Update extension and skill-sync tests plus Fusion skill docs/workflows to assert and document the new fn_* tool names
- Align product-identity strings across core, dashboard, and CLI references, including GitHub import examples, User-Agent headers, and terminal TERM_PROGRAM
- Add a @gsxdsm/fusion minor changeset describing the extension tool-prefix rename

packages/dashboard/src/github-webhooks.ts

@@ -388,7 +388,7 @@ export async function fetchInstallationToken(
           Accept: "application/vnd.github+json",
           "X-GitHub-Api-Version": "2022-11-28",
           Authorization: `Bearer ${jwt}`,
-          "User-Agent": "kb-dashboard/1.0",
+          "User-Agent": "fn/1.0",
         },
       },
     );
@@ -424,7 +424,7 @@ export async function fetchCanonicalPrInfo(
           Accept: "application/vnd.github+json",
           "X-GitHub-Api-Version": "2022-11-28",
           Authorization: `Bearer ${installationToken}`,
-          "User-Agent": "kb-dashboard/1.0",
+          "User-Agent": "fn/1.0",
         },
       },
     );
@@ -478,7 +478,7 @@ export async function fetchCanonicalIssueInfo(
           Accept: "application/vnd.github+json",
           "X-GitHub-Api-Version": "2022-11-28",
           Authorization: `Bearer ${installationToken}`,
-          "User-Agent": "kb-dashboard/1.0",
+          "User-Agent": "fn/1.0",
         },
       },
     );