fix(pi-claude-cli): unblock parameterless MCP tool calls in triage

Triage with claude-sonnet-4-6 via pi-claude-cli kept looping on
fn_review_spec calls that were rejected by pi's validator with
"root: must be object". Parameterless MCP tools (schema
{type:"object", properties:{}}) emit zero input_json_delta events,
so partialJson stayed "" and the catch fell through to
finalArgs = "" — a string, which TypeBox's Type.Object({}) rightly
refuses. Default empty partialJson to {} so the call lands.

Also:
- Add a 2-step reminder loop in triage before swapping to the
  fallback planning model — primary models that wrote PROMPT.md
  but forgot fn_review_spec recover from a nudge, no need to pay
  the cold-start tax of a new triage on a different model.
- Inject @runfusion/fusion's own pi extension into dashboard/
  daemon/serve sessions and propagate the path to createFnAgent
  via setHostExtensionPaths so fn_* tools register globally
  without requiring `pi install npm:@runfusion/fusion`.
- Drop the "historical" qualifier from replayed tool labels —
  Claude was reading "TOOL RESULT (historical Read):" as
  "previous session, ignore" and looping on verification.
- Remove subprocess-lifecycle stderr debug logs that landed for
  hang diagnosis — root cause is fixed, the noise can go.

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

packages/cli/src/commands/dashboard.ts

@@ -26,7 +26,7 @@ import {
   stopAllDevServers,
   type RuntimeLogger,
 } from "@fusion/dashboard";
-import { aiMergeTask, MissionAutopilot, MissionExecutionLoop, HeartbeatMonitor, HeartbeatTriggerScheduler, type WakeContext, ProjectEngineManager, PeerExchangeService } from "@fusion/engine";
+import { aiMergeTask, MissionAutopilot, MissionExecutionLoop, HeartbeatMonitor, HeartbeatTriggerScheduler, type WakeContext, ProjectEngineManager, PeerExchangeService, setHostExtensionPaths } from "@fusion/engine";
 import { AuthStorage, DefaultPackageManager, ModelRegistry, SettingsManager, discoverAndLoadExtensions, createExtensionRuntime } from "@mariozechner/pi-coding-agent";
 import {
   getMergeStrategy,
@@ -46,6 +46,7 @@ import {
   resolveClaudeCliExtensionPaths,
   setCachedClaudeCliResolution,
 } from "./claude-cli-extension.js";
+import { resolveSelfExtension } from "./self-extension.js";
 import { DashboardTUI, DashboardLogSink, isTTYAvailable, type SystemInfo, type GitStatus, type GitCommit, type GitCommitDetail, type GitBranch, type GitWorktree, type FileEntry, type FileReadResult, type TaskStep as TUITaskStep, type TaskLogEntry as TUITaskLogEntry, type TaskDetailData, type TaskEvent } from "./dashboard-tui/index.js";
 
 // Re-export for backward compatibility with tests
@@ -1131,9 +1132,24 @@ export async function runDashboard(port: number, opts: { paused?: boolean; dev?:
       }
     })();
 
+    // Always inject the cli's own extension (`@runfusion/fusion`) so its
+    // `fn_*` tools register globally even when the user hasn't run
+    // `pi install npm:@runfusion/fusion`. Without this, agent chat with
+    // pi-claude-cli has no fn_* tools at all.
+    const selfExtension = resolveSelfExtension();
+    const selfExtensionPaths = selfExtension.status === "ok" ? [selfExtension.path] : [];
+    if (selfExtension.status !== "ok") {
+      logSink.warn(`[extensions] self: ${selfExtension.reason}`, "extensions");
+    }
+    // Propagate self-extension path to engine so createFnAgent sessions
+    // (chat, refine, mission, etc.) also load fn_* tools, not just the
+    // dashboard's extension runtime.
+    setHostExtensionPaths(selfExtensionPaths);
+
     // Load all enabled extensions: Fusion/Pi filesystem-discovered + package-resolved.
     const extensionsResult = await discoverAndLoadExtensions(
       [
+        ...selfExtensionPaths,
         ...getEnabledPiExtensionPaths(cwd),
         ...packageExtensionPaths,
         ...claudeCliPaths,