feat: add secret detection with Secretlint (v0.8.0)

Add critical security feature to detect 350+ types of hardcoded secrets
using industry-standard Secretlint library.

Features:
- Detect AWS keys, GitHub tokens, NPM tokens, SSH keys, API keys, etc.
- All secrets marked as CRITICAL severity
- Context-aware remediation suggestions per secret type
- New SecretDetector using @secretlint/node
- New SecretViolation value object (100% test coverage)
- CLI output with "🔐 Secrets" section
- Async pipeline support for secret detection

Tests:
- Added 47 new tests (566 total, 100% pass rate)
- Coverage: 93.3% statements, 83.74% branches
- SecretViolation: 23 tests, 100% coverage
- SecretDetector: 24 tests

Dependencies:
- @secretlint/node: 11.2.5
- @secretlint/core: 11.2.5
- @secretlint/types: 11.2.5
- @secretlint/secretlint-rule-preset-recommend: 11.2.5

packages/guardian/tests/unit/infrastructure/SecretDetector.test.ts

@@ -0,0 +1,277 @@
+import { describe, it, expect, beforeEach } from "vitest"
+import { SecretDetector } from "../../../src/infrastructure/analyzers/SecretDetector"
+
+describe("SecretDetector", () => {
+    let detector: SecretDetector
+
+    beforeEach(() => {
+        detector = new SecretDetector()
+    })
+
+    describe("detectAll", () => {
+        it("should return empty array for code without secrets", async () => {
+            const code = `
+                const greeting = "Hello World"
+                const count = 42
+                function test() {
+                    return true
+                }
+            `
+
+            const violations = await detector.detectAll(code, "test.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+
+        it("should return empty array for normal environment variable usage", async () => {
+            const code = `
+                const apiKey = process.env.API_KEY
+                const dbUrl = process.env.DATABASE_URL
+            `
+
+            const violations = await detector.detectAll(code, "config.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+
+        it("should handle empty code", async () => {
+            const violations = await detector.detectAll("", "empty.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+
+        it("should handle code with only comments", async () => {
+            const code = `
+                // This is a comment
+                /* Multi-line
+                   comment */
+            `
+
+            const violations = await detector.detectAll(code, "comments.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+
+        it("should handle multiline strings without secrets", async () => {
+            const code = `
+                const template = \`
+                    Hello World
+                    This is a test
+                    No secrets here
+                \`
+            `
+
+            const violations = await detector.detectAll(code, "template.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+
+        it("should handle code with URLs", async () => {
+            const code = `
+                const apiUrl = "https://api.example.com/v1"
+                const websiteUrl = "http://localhost:3000"
+            `
+
+            const violations = await detector.detectAll(code, "urls.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+
+        it("should handle imports and requires", async () => {
+            const code = `
+                import { something } from "some-package"
+                const fs = require('fs')
+            `
+
+            const violations = await detector.detectAll(code, "imports.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+
+        it("should return violations with correct file path", async () => {
+            const code = `const secret = "test-secret-value"`
+            const filePath = "src/config/secrets.ts"
+
+            const violations = await detector.detectAll(code, filePath)
+
+            violations.forEach((v) => {
+                expect(v.file).toBe(filePath)
+            })
+        })
+
+        it("should handle .js files", async () => {
+            const code = `const test = "value"`
+
+            const violations = await detector.detectAll(code, "test.js")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+
+        it("should handle .jsx files", async () => {
+            const code = `const Component = () => <div>Test</div>`
+
+            const violations = await detector.detectAll(code, "Component.jsx")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+
+        it("should handle .tsx files", async () => {
+            const code = `const Component: React.FC = () => <div>Test</div>`
+
+            const violations = await detector.detectAll(code, "Component.tsx")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+
+        it("should handle errors gracefully", async () => {
+            const code = null as unknown as string
+
+            const violations = await detector.detectAll(code, "test.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+
+        it("should handle malformed code gracefully", async () => {
+            const code = "const = = ="
+
+            const violations = await detector.detectAll(code, "malformed.ts")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+    })
+
+    describe("parseOutputToViolations", () => {
+        it("should parse empty output", async () => {
+            const code = ""
+
+            const violations = await detector.detectAll(code, "test.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+
+        it("should handle whitespace-only output", async () => {
+            const code = "   \n   \n   "
+
+            const violations = await detector.detectAll(code, "test.ts")
+
+            expect(violations).toHaveLength(0)
+        })
+    })
+
+    describe("extractSecretType", () => {
+        it("should handle various secret types correctly", async () => {
+            const code = `const value = "test"`
+
+            const violations = await detector.detectAll(code, "test.ts")
+
+            violations.forEach((v) => {
+                expect(v.secretType).toBeTruthy()
+                expect(typeof v.secretType).toBe("string")
+                expect(v.secretType.length).toBeGreaterThan(0)
+            })
+        })
+    })
+
+    describe("integration", () => {
+        it("should work with TypeScript code", async () => {
+            const code = `
+                interface Config {
+                    apiKey: string
+                }
+
+                const config: Config = {
+                    apiKey: process.env.API_KEY || "default"
+                }
+            `
+
+            const violations = await detector.detectAll(code, "config.ts")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+
+        it("should work with ES6+ syntax", async () => {
+            const code = `
+                const fetchData = async () => {
+                    const response = await fetch(url)
+                    return response.json()
+                }
+
+                const [data, setData] = useState(null)
+            `
+
+            const violations = await detector.detectAll(code, "hooks.ts")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+
+        it("should work with JSX/TSX", async () => {
+            const code = `
+                export const Button = ({ onClick }: Props) => {
+                    return <button onClick={onClick}>Click me</button>
+                }
+            `
+
+            const violations = await detector.detectAll(code, "Button.tsx")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+
+        it("should handle concurrent detections", async () => {
+            const code1 = "const test1 = 'value1'"
+            const code2 = "const test2 = 'value2'"
+            const code3 = "const test3 = 'value3'"
+
+            const [result1, result2, result3] = await Promise.all([
+                detector.detectAll(code1, "file1.ts"),
+                detector.detectAll(code2, "file2.ts"),
+                detector.detectAll(code3, "file3.ts"),
+            ])
+
+            expect(result1).toBeInstanceOf(Array)
+            expect(result2).toBeInstanceOf(Array)
+            expect(result3).toBeInstanceOf(Array)
+        })
+    })
+
+    describe("edge cases", () => {
+        it("should handle very long code", async () => {
+            const longCode = "const value = 'test'\n".repeat(1000)
+
+            const violations = await detector.detectAll(longCode, "long.ts")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+
+        it("should handle special characters in code", async () => {
+            const code = `
+                const special = "!@#$%^&*()_+-=[]{}|;:',.<>?"
+                const unicode = "日本語 🚀"
+            `
+
+            const violations = await detector.detectAll(code, "special.ts")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+
+        it("should handle code with regex patterns", async () => {
+            const code = `
+                const pattern = /^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,}$/i
+                const matches = text.match(pattern)
+            `
+
+            const violations = await detector.detectAll(code, "regex.ts")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+
+        it("should handle code with template literals", async () => {
+            const code = `
+                const message = \`Hello \${name}, your balance is \${balance}\`
+            `
+
+            const violations = await detector.detectAll(code, "template.ts")
+
+            expect(violations).toBeInstanceOf(Array)
+        })
+    })
+})