refactor(agent): unified transcript block finalization logic

- Replaced commit-based stability checks with a unified `isTranscriptBlockFinalized` tracking mechanism.
- Removed deprecated provisional rendering configuration and flags across tool and renderer interfaces.
- Standardized native scrollback boundary logic to pin at the first unfinalized block using settled row verification.
- Updated and refactored test suites to validate block finalization and settled row boundaries instead of deprecated commit stability methods.

packages/coding-agent/test/tools/eval-commit-stability.test.ts

@@ -1,27 +1,4 @@
-/**
- * Regression: under heavy concurrent `agent()`/`parallel()` fan-out inside an
- * eval cell, `renderAgentProgressEvents` mutates on almost every progress tick
- * — a per-subagent "current tool" line is inserted/removed as each subagent
- * starts/stops a tool call, and status icon/stats/duration tick on already-
- * rendered rows — while `options.isPartial` holds `true` for the WHOLE eval
- * cell (agent progress ticks never carry an `async` completed/failed state, so
- * `event-controller.ts`'s `#handleToolExecutionUpdate` keeps passing
- * `isPartial: true` to `ToolExecutionComponent.updateResult` throughout).
- *
- * Without `evalToolRenderer.provisionalPartialResult: true`,
- * `ToolExecutionComponent.isTranscriptBlockCommitStable()` reports the eval
- * block as commit-stable while partial. That lets the transcript's stable-prefix
- * ratchet (`deriveLiveCommitState`) promote agent-progress rows that keep
- * mutating (a "slow ticker") into native scrollback, and `packages/tui`'s
- * committed-prefix resync then repeatedly re-shows the frame tail under its
- * "duplication, never loss" contract — producing the reported
- * overlapping/duplicated status-tree rows. Contract: while a partial eval
- * result is in flight the block reports commit-unstable so the ratchet keeps
- * its rows in the live region; once the cell settles (`isPartial === false`)
- * it is commit-stable again. The opt-in is renderer-scoped (matches the
- * `sshToolRenderer` precedent for issue #3177).
- */
-import { afterEach, beforeAll, describe, expect, it, vi } from "bun:test";
+import { beforeAll, describe, expect, it } from "bun:test";
 import { resetSettingsForTest, Settings } from "@oh-my-pi/pi-coding-agent/config/settings";
 import type { EvalStatusEvent, EvalToolDetails } from "@oh-my-pi/pi-coding-agent/eval/types";
 import { ToolExecutionComponent } from "@oh-my-pi/pi-coding-agent/modes/components/tool-execution";
@@ -34,10 +11,6 @@ function makeEvalComponent() {
 	return new ToolExecutionComponent("eval", { code: "parallel([...])", language: "python" }, {}, undefined, uiStub);
 }
 
-function partialResult(text: string) {
-	return { content: [{ type: "text" as const, text }] };
-}
-
 /** Build an eval result whose `details.cells` carry agent-fan-out progress. */
 function evalAgentResult(events: EvalStatusEvent[], text = "") {
 	const details: EvalToolDetails = {
@@ -58,63 +31,50 @@ function evalAgentResult(events: EvalStatusEvent[], text = "") {
 	return { content: [{ type: "text" as const, text }], details };
 }
 
-describe("eval tool block commit stability", () => {
+function expectLive(component: ToolExecutionComponent): void {
+	expect(component.isTranscriptBlockFinalized()).toBe(false);
+	expect(component.getNativeScrollbackLiveRegionStart()).toBe(0);
+}
+
+function expectFinal(component: ToolExecutionComponent): void {
+	expect(component.isTranscriptBlockFinalized()).toBe(true);
+	expect(component.getNativeScrollbackLiveRegionStart()).toBeUndefined();
+}
+
+describe("eval tool transcript finalization", () => {
 	beforeAll(async () => {
 		resetSettingsForTest();
 		await Settings.init({ inMemory: true });
 		await initTheme();
 	});
 
-	afterEach(() => {
-		vi.restoreAllMocks();
-	});
-
-	it("reports commit-unstable while an eval result is partial", () => {
+	it("keeps partial eval results in the native-scrollback live region", () => {
 		const component = makeEvalComponent();
+
 		component.updateResult(evalAgentResult([{ op: "agent", id: "a1", status: "running" }]), true);
 
-		expect(component.isTranscriptBlockFinalized()).toBe(false);
-		expect(component.isTranscriptBlockCommitStable()).toBe(false);
+		expectLive(component);
 	});
 
-	it("flips commit-stable as soon as the eval result settles", () => {
+	it("moves the block out of the live region as soon as the eval result settles", () => {
 		const component = makeEvalComponent();
 		component.updateResult(evalAgentResult([{ op: "agent", id: "a1", status: "running" }]), true);
-		expect(component.isTranscriptBlockCommitStable()).toBe(false);
+		expectLive(component);
 
-		component.updateResult(partialResult("done\n"), false);
-		expect(component.isTranscriptBlockFinalized()).toBe(true);
-		expect(component.isTranscriptBlockCommitStable()).toBe(true);
+		component.updateResult({ content: [{ type: "text" as const, text: "done\n" }] }, false);
+
+		expectFinal(component);
 	});
 
-	it("does not opt other foreground tools out of partial-result stream commits", () => {
-		// Sanity: bash and friends still get the existing `isPartial`
-		// commit-stable behaviour — the eval opt-in must be renderer-scoped.
-		const component = new ToolExecutionComponent("bash", { command: "ls" }, {}, undefined, uiStub);
-		component.updateResult(partialResult("a\nb\n"), true);
-
-		expect(component.isTranscriptBlockFinalized()).toBe(false);
-		expect(component.isTranscriptBlockCommitStable()).toBe(true);
-	});
-
-	it("stays commit-unstable across agent-progress churn while partial", () => {
-		// Defends the fix regardless of which specific row mutated: a subagent
-		// starting a tool inserts a `currentTool` line; stopping it removes one.
-		// Both shapes must read commit-unstable while `isPartial` holds, so the
-		// ratchet never promotes either into native scrollback mid-flight.
+	it("stays in the live region across agent-progress shape churn while partial", () => {
 		const component = makeEvalComponent();
 
-		// First tick: one running subagent with a current-tool line present.
 		component.updateResult(
 			evalAgentResult([{ op: "agent", id: "a1", status: "running", currentTool: "read" }]),
 			true,
 		);
-		expect(component.isTranscriptBlockFinalized()).toBe(false);
-		expect(component.isTranscriptBlockCommitStable()).toBe(false);
+		expectLive(component);
 
-		// Second tick: the current-tool line is gone (subagent between tools),
-		// and a second subagent has joined — row count and per-row content both
-		// changed. Still partial, still commit-unstable.
 		component.updateResult(
 			evalAgentResult([
 				{ op: "agent", id: "a1", status: "running" },
@@ -122,7 +82,7 @@ describe("eval tool block commit stability", () => {
 			]),
 			true,
 		);
-		expect(component.isTranscriptBlockFinalized()).toBe(false);
-		expect(component.isTranscriptBlockCommitStable()).toBe(false);
+
+		expectLive(component);
 	});
 });