refactor(workflow): drop Finalized.pushed_branch

Dead state — constructed in pull_request.rs from run_options.run_branch()
but no consumer ever reads it. Concluded's pushed_branch was dropped in
the prior simplify pass; Finalized was the sibling still carrying it.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/crates/fabro-workflow/src/pipeline/pull_request.rs

@@ -580,7 +580,6 @@ pub async fn pull_request(concluded: Concluded, options: &PullRequestOptions) ->
         run_id: run_options.run_id,
         outcome,
         conclusion,
-        pushed_branch: run_options.run_branch().map(str::to_string),
         pr_url,
     }
 }

lib/crates/fabro-workflow/src/pipeline/types.rs

@@ -307,11 +307,10 @@ pub struct Concluded {
 /// Output of the PULL_REQUEST phase.
 #[non_exhaustive]
 pub struct Finalized {
-    pub run_id:        RunId,
-    pub outcome:       Result<Outcome, Error>,
-    pub conclusion:    Conclusion,
-    pub pushed_branch: Option<String>,
-    pub pr_url:        Option<String>,
+    pub run_id:     RunId,
+    pub outcome:    Result<Outcome, Error>,
+    pub conclusion: Conclusion,
+    pub pr_url:     Option<String>,
 }
 
 /// Options for the TRANSFORM phase.