feat(coding-agent): added per-turn AUTO_THINKING in coding-agent session

- Added AUTO_THINKING as a configured thinking level in settings, schema, SDK, and session plumbing.
- Implemented per-turn auto reasoning classification with online/local prompts, effort clamping, and skip guards.
- Updated model selectors, ACP options, footer/status UI, and events to render auto and auto->resolved states.
- Added AUTO_THINKING parse/clamp tests and fixed local-module cycle and hashline preview regressions.

packages/coding-agent/test/auto-thinking-classifier.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it } from "bun:test";
+import { ThinkingLevel } from "@oh-my-pi/pi-agent-core";
+import { Effort, getBundledModel } from "@oh-my-pi/pi-ai";
+import {
+	AUTO_THINKING,
+	clampAutoThinkingEffort,
+	parseConfiguredThinkingLevel,
+	parseThinkingLevel,
+} from "@oh-my-pi/pi-coding-agent/thinking";
+import { parseDifficultyBucket, parseDifficultyLevel } from "../src/auto-thinking/classifier";
+
+describe("auto thinking classifier helpers", () => {
+	it("parses configured thinking without widening provider-facing thinking selectors", () => {
+		expect(parseConfiguredThinkingLevel(AUTO_THINKING)).toBe(AUTO_THINKING);
+		expect(parseConfiguredThinkingLevel(Effort.High)).toBe(Effort.High);
+		expect(parseConfiguredThinkingLevel("bogus")).toBeUndefined();
+		expect(parseThinkingLevel(AUTO_THINKING)).toBeUndefined();
+		expect(parseThinkingLevel(ThinkingLevel.Off)).toBe(ThinkingLevel.Off);
+	});
+
+	it("maps online 4-way classifier labels to effort levels", () => {
+		expect(parseDifficultyLevel("x-high")).toBe(Effort.XHigh);
+		expect(parseDifficultyLevel("The answer is HIGH.")).toBe(Effort.High);
+		expect(parseDifficultyLevel("med")).toBe(Effort.Medium);
+		expect(parseDifficultyLevel("low")).toBe(Effort.Low);
+		expect(parseDifficultyLevel("unknown")).toBeUndefined();
+	});
+
+	it("maps local 3-bucket labels to coarse effort levels", () => {
+		expect(parseDifficultyBucket("trivial")).toBe(Effort.Low);
+		expect(parseDifficultyBucket("moderate")).toBe(Effort.High);
+		expect(parseDifficultyBucket("hard")).toBe(Effort.XHigh);
+		expect(parseDifficultyBucket("medium")).toBeUndefined();
+	});
+
+	it("clamps auto effort to model support while never resolving below low", () => {
+		const model = getBundledModel("anthropic", "claude-sonnet-4-6");
+		if (!model) throw new Error("Expected bundled Claude Sonnet 4.6 model");
+
+		expect(clampAutoThinkingEffort(model, Effort.XHigh)).toBe(Effort.High);
+		expect(clampAutoThinkingEffort(model, Effort.Minimal)).toBe(Effort.Low);
+	});
+});