fix: lane sessions find task-runner from installed package

extensions/taskplane/engine.ts

@@ -817,18 +817,30 @@ export async function executeOrchBatch(
 				batchState.skippedTasks,
 				batchState.blockedTasks,
 				totalElapsedSec,
+				batchState.orchBranch,
+				batchState.baseBranch,
 			),
 			batchState.failedTasks > 0 ? "warning" : "info",
 		);
 
-		// ── TS-009: Delete state file on clean completion (no failures) ──
+		// ── Preserve state for /orch-integrate when orch branch exists ──
+		// If integration is "manual" and we have an orch branch, keep the
+		// state file so /orch-integrate can find orchBranch and baseBranch.
+		// Only delete state if there's no orch branch to integrate.
 		if (batchState.phase === "completed") {
-			try {
-				deleteBatchState(stateRoot);
-				execLog("state", batchState.batchId, "state file deleted on clean completion");
-			} catch (err: unknown) {
-				const msg = err instanceof Error ? err.message : String(err);
-				execLog("state", batchState.batchId, `failed to delete state file: ${msg}`);
+			if (batchState.orchBranch) {
+				execLog("state", batchState.batchId, "state file preserved for /orch-integrate", {
+					orchBranch: batchState.orchBranch,
+				});
+			} else {
+				// Legacy mode (no orch branch) — clean up state
+				try {
+					deleteBatchState(stateRoot);
+					execLog("state", batchState.batchId, "state file deleted on clean completion");
+				} catch (err: unknown) {
+					const msg = err instanceof Error ? err.message : String(err);
+					execLog("state", batchState.batchId, `failed to delete state file: ${msg}`);
+				}
 			}
 		}
 	}

extensions/taskplane/execution.ts

@@ -11,6 +11,53 @@ import type { AllocatedLane, AllocatedTask, DependencyGraph, LaneExecutionResult
 import { allocateLanes } from "./waves.ts";
 import { runGit } from "./git.ts";
 
+// ── Task Runner Extension Path Resolution ────────────────────────────
+
+/**
+ * Find the task-runner extension path for lane sessions.
+ *
+ * Resolution order:
+ *   1. Local project: {repoRoot}/extensions/task-runner.ts (for taskplane dev)
+ *   2. Global npm (Windows): {APPDATA}/npm/node_modules/taskplane/extensions/task-runner.ts
+ *   3. Global npm (Unix): /usr/local/lib/node_modules/taskplane/extensions/task-runner.ts
+ *   4. npm peer: resolve from pi's location
+ *
+ * @throws ExecutionError if task-runner.ts cannot be found anywhere
+ */
+function resolveTaskRunnerExtensionPath(repoRoot: string): string {
+	const extFile = join("extensions", "task-runner.ts");
+
+	// 1. Local project (taskplane development)
+	const localPath = join(resolve(repoRoot), extFile);
+	if (existsSync(localPath)) return localPath;
+
+	// 2. Global npm install paths
+	const home = process.env.HOME || process.env.USERPROFILE || "";
+	const candidates: string[] = [];
+	if (process.env.APPDATA) {
+		candidates.push(join(process.env.APPDATA, "npm", "node_modules", "taskplane", extFile));
+	}
+	if (home) {
+		candidates.push(join(home, "AppData", "Roaming", "npm", "node_modules", "taskplane", extFile));
+		candidates.push(join(home, ".npm-global", "lib", "node_modules", "taskplane", extFile));
+	}
+	candidates.push(join("/usr", "local", "lib", "node_modules", "taskplane", extFile));
+
+	// 3. Peer of pi's package
+	try {
+		const piPath = process.argv[1] || "";
+		const piPkgDir = resolve(piPath, "..", "..");
+		candidates.push(join(piPkgDir, "..", "taskplane", extFile));
+	} catch { /* ignore */ }
+
+	for (const candidate of candidates) {
+		if (existsSync(candidate)) return candidate;
+	}
+
+	// Fallback: return the local path (will fail at spawn time with a clear error)
+	return localPath;
+}
+
 // ── Execution Helpers ────────────────────────────────────────────────
 
 /**
@@ -206,7 +253,7 @@ export function buildTmuxSpawnArgs(
 		.map(([key, val]) => `${key}=${shellQuote(val)}`)
 		.join(" ");
 
-	const taskRunnerExtPath = join(resolve(repoRoot), "extensions", "task-runner.ts");
+	const taskRunnerExtPath = resolveTaskRunnerExtensionPath(repoRoot);
 	const basePiCommand = `${envParts} pi --no-session -e ${shellQuote(taskRunnerExtPath)}`;
 
 	// NOTE: Do not redirect lane output here. Shell redirection has proven

extensions/taskplane/messages.ts

@@ -36,7 +36,7 @@ export const ORCH_MESSAGES = {
 		`🔀 [Wave ${waveNum}] Merge: placeholder — Step 3 (TS-008) will replace with mergeWave()`,
 	orchWorktreeReset: (waveNum: number, lanes: number) =>
 		`🔄 Resetting ${lanes} worktree(s) to target branch HEAD after wave ${waveNum}`,
-	orchBatchComplete: (batchId: string, succeeded: number, failed: number, skipped: number, blocked: number, elapsedSec: number) => {
+	orchBatchComplete: (batchId: string, succeeded: number, failed: number, skipped: number, blocked: number, elapsedSec: number, orchBranch?: string, baseBranch?: string) => {
 		const lines = [`\n🏁 Batch ${batchId} complete: ${succeeded} succeeded, ${failed} failed, ${skipped} skipped, ${blocked} blocked (${elapsedSec}s)`];
 		if (failed > 0 || blocked > 0) {
 			lines.push("");
@@ -48,6 +48,17 @@ export const ORCH_MESSAGES = {
 			lines.push("   • /orch-resume     — retry from the failed wave");
 			lines.push("   • /orch-abort      — clean up and start fresh");
 		}
+		if (orchBranch && succeeded > 0) {
+			lines.push("");
+			lines.push(`   ℹ Orch branch: ${orchBranch}`);
+			if (baseBranch) {
+				lines.push(`   Review changes: git log ${baseBranch}..${orchBranch}`);
+			}
+			lines.push("   Next steps:");
+			lines.push("   • /orch-integrate          — fast-forward into your branch");
+			lines.push("   • /orch-integrate --merge   — merge (if branches diverged)");
+			lines.push("   • /orch-integrate --pr      — push and open a PR");
+		}
 		return lines.join("\n");
 	},
 	orchBatchFailed: (batchId: string, reason: string) =>