feat(FN-3332): add droid runtime plugin with event bridge and process manag

The merge delivers a new `fusion-plugin-droid-runtime` plugin providing a full MCP server and runtime adapter for droid-based agents, with event bridging, process management, tool mapping, and a prompt builder. It also adds agent delegation and org hierarchy tools to the pi extension, while fixing a

Fusion-Task-Id: FN-3332

plugins/fusion-plugin-droid-runtime/src/thinking-config.ts

@@ -0,0 +1,83 @@
+/**
+ * Thinking effort configuration for mapping pi's ThinkingLevel to Droid CLI --effort flags.
+ *
+ * Maps pi's reasoning levels (minimal/low/medium/high/xhigh) to the CLI's effort
+ * levels (low/medium/high/max). Opus models get an elevated mapping where medium
+ * becomes high and high becomes max, leveraging their superior reasoning capability.
+ *
+ * IMPORTANT: The CLI does NOT support --thinking-budget. Only --effort is supported.
+ */
+
+import type { ThinkingLevel, ThinkingBudgets } from "@mariozechner/pi-ai";
+
+/** CLI effort levels accepted by the --effort flag */
+export type CliEffortLevel = "low" | "medium" | "high" | "max";
+
+/**
+ * Standard model mapping: pi ThinkingLevel -> CLI effort.
+ * Non-Opus models never receive "max" (would cause CLI error).
+ */
+const STANDARD_EFFORT_MAP: Record<ThinkingLevel, CliEffortLevel> = {
+  minimal: "low",
+  low: "low",
+  medium: "medium",
+  high: "high",
+  xhigh: "high", // non-Opus: silently downgrade (max not supported)
+};
+
+/**
+ * Opus model mapping: shifted up for elevated reasoning.
+ * Opus models get max capability at high/xhigh levels.
+ */
+const OPUS_EFFORT_MAP: Record<ThinkingLevel, CliEffortLevel> = {
+  minimal: "low",
+  low: "low",
+  medium: "high", // shifted: standard high
+  high: "max", // shifted: maximum capability
+  xhigh: "max", // Opus gets max
+};
+
+/**
+ * Detect whether a model ID refers to an Opus model.
+ * Uses includes('opus') for forward-compatibility with future Opus versions.
+ *
+ * @param modelId - The model identifier string
+ * @returns true if the model is an Opus variant
+ */
+export function isOpusModel(modelId: string): boolean {
+  return modelId.includes("opus");
+}
+
+/**
+ * Map pi's ThinkingLevel to a CLI effort string.
+ *
+ * When reasoning is undefined, returns undefined so the --effort flag is omitted
+ * entirely, letting the CLI use its default behavior. When thinkingBudgets are
+ * provided, a console.warn is logged because the CLI only supports effort levels,
+ * not token budgets.
+ *
+ * @param reasoning - Pi's thinking level (undefined = omit flag)
+ * @param modelId - Model ID for Opus detection
+ * @param thinkingBudgets - Custom budgets (logged as unsupported, not applied)
+ * @returns CLI effort level string, or undefined if flag should be omitted
+ */
+export function mapThinkingEffort(
+  reasoning?: ThinkingLevel,
+  modelId?: string,
+  thinkingBudgets?: ThinkingBudgets,
+): CliEffortLevel | undefined {
+  if (reasoning === undefined) {
+    return undefined; // omit --effort flag entirely
+  }
+
+  if (thinkingBudgets && Object.keys(thinkingBudgets).length > 0) {
+    console.warn(
+      "[droid-cli] Custom thinkingBudgets are not supported with CLI subprocess. " +
+        "The CLI uses --effort levels instead of token budgets. Budgets will be ignored.",
+    );
+  }
+
+  const isOpus = modelId ? isOpusModel(modelId) : false;
+  const map = isOpus ? OPUS_EFFORT_MAP : STANDARD_EFFORT_MAP;
+  return map[reasoning];
+}