feat(codex): inject windows git bash guidance

Plan: plans/codex-windows-git-bash-profile.md

packages/omo-codex/plugin/components/rules/bundled-rules/windows-git-bash.md

@@ -0,0 +1,10 @@
+---
+description: Windows Git Bash guidance for Codex
+alwaysApply: true
+---
+
+On Windows native Codex sessions, prefer Git Bash for shell commands.
+
+Use `shell: "bash"` when `bash.exe` is on PATH. Otherwise use the absolute Git Bash path from `OMO_CODEX_GIT_BASH_PATH` or `C:\Program Files\Git\bin\bash.exe`.
+
+Use PowerShell only for Windows-native operations that need PowerShell.

packages/omo-codex/plugin/components/rules/test/package-smoke.test.ts

@@ -1,4 +1,4 @@
-import { readFileSync } from "node:fs";
+import { readdirSync, readFileSync } from "node:fs";
 import { describe, expect, it } from "vitest";
 
 type PackageJson = {
@@ -51,6 +51,7 @@ describe("plugin package metadata", () => {
 		const pluginJson = readPluginJson(".codex-plugin/plugin.json");
 		const hooksJson = readHooksJson("hooks/hooks.json");
 		const cliSource = readFileSync("src/cli.ts", "utf8");
+		const bundledRules = readdirSync("bundled-rules").sort();
 
 		// when
 		const hookConfig = hooksJson.hooks;
@@ -69,6 +70,7 @@ describe("plugin package metadata", () => {
 		expect(packageJson.dependencies ?? {}).toEqual({ picomatch: "^4.0.3" });
 		expect(packageJson.bin["omo-rules"]).toBe("./dist/cli.js");
 		expect(packageJson.files).toContain("bundled-rules");
+		expect(bundledRules).toContain("windows-git-bash.md");
 		expect(pluginJson.hooks).toBe("./hooks/hooks.json");
 		expect(cliSource.startsWith("#!/usr/bin/env node")).toBe(true);
 		expect(commands).toEqual([

packages/omo-codex/plugin/components/rules/test/windows-git-bash-bundled-rule.test.ts

@@ -0,0 +1,97 @@
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, describe, expect, it } from "vitest";
+
+import { runSessionStartHook, type CodexSessionStartInput } from "../src/codex-hook.js";
+import { findPluginBundledCandidates } from "../src/rules/finder.js";
+
+const WINDOWS_RULE_DESCRIPTION = "Windows Git Bash guidance for Codex";
+const WINDOWS_RULE_PATH = "bundled-rules/windows-git-bash.md";
+const WINDOWS_GUIDANCE = "On Windows native Codex sessions, prefer Git Bash for shell commands.";
+const BUNDLED_ONLY_ENV = {
+	CODEX_RULES_ENABLED_SOURCES: "plugin-bundled",
+};
+const PROJECT_AND_BUNDLED_ENV = {
+	CODEX_RULES_ENABLED_SOURCES: ".omo/rules,plugin-bundled",
+};
+const tempDirectories: string[] = [];
+let originalPluginRoot: string | undefined;
+
+afterEach(() => {
+	restoreEnv("PLUGIN_ROOT", originalPluginRoot);
+	for (const directory of tempDirectories.splice(0)) {
+		rmSync(directory, { recursive: true, force: true });
+	}
+});
+
+function makeProject(): { readonly root: string; readonly pluginData: string } {
+	originalPluginRoot = process.env["PLUGIN_ROOT"];
+	process.env["PLUGIN_ROOT"] = process.cwd();
+	const root = mkdtempSync(join(tmpdir(), "codex-rules-windows-git-bash-project-"));
+	const pluginData = mkdtempSync(join(tmpdir(), "codex-rules-windows-git-bash-data-"));
+	tempDirectories.push(root, pluginData);
+	writeFileSync(join(root, "package.json"), JSON.stringify({ name: "fixture" }));
+	return { root, pluginData };
+}
+
+function sessionStartInput(root: string): CodexSessionStartInput {
+	return {
+		session_id: "session-1",
+		transcript_path: null,
+		cwd: root,
+		hook_event_name: "SessionStart",
+		model: "gpt-5.5",
+		permission_mode: "default",
+		source: "startup",
+	};
+}
+
+function restoreEnv(name: string, value: string | undefined): void {
+	if (value === undefined) {
+		delete process.env[name];
+		return;
+	}
+	process.env[name] = value;
+}
+
+function occurrenceCount(value: string, search: string): number {
+	return value.split(search).length - 1;
+}
+
+describe("Windows Git Bash bundled rule", () => {
+	it("#given packaged bundled rules #when discovering plugin-bundled candidates #then Windows Git Bash rule is included", () => {
+		const candidates = findPluginBundledCandidates({ pluginRoot: process.cwd() });
+
+		expect(candidates.map((candidate) => candidate.relativePath)).toContain(WINDOWS_RULE_PATH);
+	});
+
+	it("#given bundled rules enabled #when SessionStart runs #then Windows Git Bash guidance is injected once", async () => {
+		const { root, pluginData } = makeProject();
+
+		const output = await runSessionStartHook(sessionStartInput(root), {
+			pluginDataRoot: pluginData,
+			env: BUNDLED_ONLY_ENV,
+		});
+
+		expect(occurrenceCount(output, WINDOWS_GUIDANCE)).toBe(1);
+	});
+
+	it("#given project rule with same description #when static rules load #then project guidance overrides bundled guidance", async () => {
+		const { root, pluginData } = makeProject();
+		const projectGuidance = "Project-specific Windows shell policy.";
+		mkdirSync(join(root, ".omo", "rules"), { recursive: true });
+		writeFileSync(
+			join(root, ".omo", "rules", "windows-git-bash.md"),
+			["---", `description: ${WINDOWS_RULE_DESCRIPTION}`, "alwaysApply: true", "---", "", projectGuidance].join("\n"),
+		);
+
+		const output = await runSessionStartHook(sessionStartInput(root), {
+			pluginDataRoot: pluginData,
+			env: PROJECT_AND_BUNDLED_ENV,
+		});
+
+		expect(output).toContain(projectGuidance);
+		expect(output).not.toContain(WINDOWS_GUIDANCE);
+	});
+});