feat(FN-4148): derive GitHub tracking titles from task descriptions

Adds GitHub tracking title derivation so tasks can display meaningful titles when PR/issue tracking data is incomplete, falling back to the task description. The core implementation lives in `github-tracking.ts` with expanded test coverage across the tracking suite, and the feature is wired into pla

Fusion-Task-Id: FN-4148

Fusion-Task-Lineage: d57c6279-1b4f-4ade-9c3f-e20ac391ea45

packages/dashboard/src/routes/register-planning-subtask-routes.ts

@@ -21,6 +21,7 @@ async function maybeCreateTaskTrackingIssue(taskStore: TaskStore, task: import("
       taskStore,
       projectSettings,
       globalSettings,
+      rootDir: taskStore.getRootDir(),
       logger: console,
     });
   } catch {

packages/dashboard/src/routes/register-task-workflow-routes.ts

@@ -108,6 +108,7 @@ async function maybeCreateTaskTrackingIssue(taskStore: TaskStore, task: Task, op
       taskStore,
       projectSettings: trackingProjectSettings,
       globalSettings,
+      rootDir: taskStore.getRootDir(),
       logger: console,
     });
   } catch {