review/incremental-review: always submit review, never call report_progress (#516)

* WIP

* WIP

* review/incremental-review: always submit review, never call report_progress

The progress comment is auto-deleted by the stranded-comment cleanup in
main.ts when the agent skips report_progress. This makes reviews the
sole PR artifact for both modes, reducing noise.

- soften report_progress tool description to allow mode opt-out
- Review mode: always submit exactly one review (approve or request changes)
- IncrementalReview mode: submit review for substantive outcomes, silently
  exit for non-substantive changes (formatting-only pushes produce zero artifacts)

Made-with: Cursor

* incremental-review: clarify approval condition for substantive no-issues case

Made-with: Cursor

* report_progress: s/completed/current task list

Made-with: Cursor

* system instructions: align report_progress guidance with mode opt-out

Made-with: Cursor

mcp/comment.ts

@@ -400,7 +400,7 @@ export function ReportProgressTool(ctx: ToolContext) {
   return tool({
     name: "report_progress",
     description:
-      "Share progress on the associated GitHub issue/PR. The first call creates a comment; subsequent calls update it in place. You MUST call this at the end of every run with a brief final summary (1-3 sentences). The completed task list is automatically appended in a collapsible section — do not restate individual steps.",
+      "Share progress on the associated GitHub issue/PR. The first call creates a comment; subsequent calls update it in place. Call this at the end of every run with a brief final summary (1-3 sentences) unless the mode guidance instructs otherwise. The current task list is automatically appended in a collapsible section — do not restate individual steps.",
     parameters: ReportProgress,
     execute: execute(async (params) => {
       let body = params.body;