chore: improve documentation and tooling configuration (#23)

Author: roottool

.github/renovate.json

@@ -1,6 +1,6 @@
 {
 	"$schema": "https://docs.renovatebot.com/renovate-schema.json",
-	"extends": ["config:best-practices"],
+	"extends": ["config:best-practices", "customManagers:biomeVersions"],
 	"timezone": "Asia/Tokyo",
 	"schedule": ["before 5am on Monday"],
 	"labels": ["dependencies"],

AGENTS.md

@@ -103,6 +103,17 @@ For implementation-level security constraints, see the **Security rules (mandato
 
 ---
 
+## Key validation criteria
+
+To maintain a predictable boundary, keys must meet the following criteria. Failure to do so results in an `invalid_key` issue.
+
+- **Non-empty**: A key must have a length > 0.
+  - Note: Keys consisting only of whitespace characters are considered valid as they satisfy the length requirement and preserve the "opaque strings" principle.
+- **Valid Type**: A key must be a string (FormData specifications generally ensure this, but the parser must enforce it).
+- **No reserved names**: While "opaque", keys that interfere with basic object access or are inherently ambiguous in a flat structure are rejected.
+
+---
+
 ## ParseIssue contract
 
 ### Allowed IssueCode values (fixed)

package.json

@@ -37,11 +37,11 @@
 		"lint": "oxlint . --deny-warnings",
 		"lint:fix": "oxlint . --fix-suggestions",
 		"check:type": "tsc --noEmit",
-		"format:biome": "biome format --write",
+		"format:biome": "biome check --write --assist-enabled true",
 		"format:prettier": "prettier --cache --write \"**/*.{md,yml,yaml}\"",
 		"format": "npm-run-all2 format:biome format:prettier",
 		"fix": "npm-run-all2 lint:fix format",
-		"check:biome": "biome format .",
+		"check:biome": "biome check . --assist-enabled true",
 		"check:prettier": "prettier --cache --check \"**/*.{md,yml,yaml}\"",
 		"check:format": "npm-run-all2 check:biome check:prettier",
 		"check:source": "npm-run-all2 lint check:format",

src/issues/createIssue.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { createIssue } from "#issues/createIssue";
 import type { ParseIssue } from "#types/ParseIssue";
 

src/issues/createIssue.ts

@@ -1,5 +1,5 @@
-import type { ParseIssue } from "#types/ParseIssue";
 import type { IssueCode } from "#types/IssueCode";
+import type { ParseIssue } from "#types/ParseIssue";
 
 /**
  * Payload for creating a ParseIssue.

src/issues/forbiddenKeys.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { FORBIDDEN_KEYS } from "#issues/forbiddenKeys";
 
 describe("FORBIDDEN_KEYS", () => {

src/parse.test.ts

@@ -1,4 +1,4 @@
-import { assert, describe, it, expect } from "vitest";
+import { assert, describe, expect, it } from "vitest";
 import { parse } from "#parse";
 
 describe("valid input", () => {

src/parse.ts

@@ -1,5 +1,5 @@
-import { FORBIDDEN_KEYS } from "#issues/forbiddenKeys";
 import { createIssue } from "#issues/createIssue";
+import { FORBIDDEN_KEYS } from "#issues/forbiddenKeys";
 import type { ParseResult } from "#types/ParseResult";
 
 /**