docs: streamline bilingual README and consolidate detailed guides

TESTING_GUIDE.md

@@ -312,6 +312,8 @@ Use the full suite by default. Use targeted filters only while iterating locally
 
 ## Test Layout
 
+`DocumentationStatusContractTests` checks the status fields in `DEVELOPER_GUIDE.md` and `AGENT_GUIDE.md`, plus README links to both language versions of the developer reference. `LicensePolicyTests` keeps bilingual license notices while requiring only one README badge block.
+
 The test project mirrors the production areas closely.
 Use `docs/test-doc-maintenance-plan.md` before moving oversized suites or adding `Skip =` cases; it tracks the current split sequence, skip classifications, and large-document boundaries.
 Candidate-ordered parallel-index recovery tests must prove that the fatal result returns while the earlier contract candidate remains blocked and the parallel workers have not stopped. Assert those synchronization states instead of a narrow wall-clock threshold so the regression remains detectable under full-suite contention.
@@ -1643,6 +1645,8 @@ dotnet test --filter "FullyQualifiedName~GitHelperTests"
 
 ## テスト構成
 
+`DocumentationStatusContractTests` は `DEVELOPER_GUIDE.md` と `AGENT_GUIDE.md` の status フィールド、および README から日英の開発者向け参照へのリンクを検証します。`LicensePolicyTests` は日英のライセンス表記と、README にバッジが1組だけあることを確認します。
+
 テストプロジェクトは、本番コードの責務にかなり近い形で分かれています。
 巨大 suite を移動する場合や `Skip =` case を追加する場合は、現在の分割順序、skip 分類、巨大ドキュメントの境界を追跡する `docs/test-doc-maintenance-plan.md` を先に確認してください。
 候補順序に基づく parallel index recovery のテストでは、先行する contract 候補が block されたまま、かつ parallel worker が停止する前に fatal result が返ることを検証してください。full-suite の競合下でも回帰を検出できるよう、狭い wall-clock threshold の代わりにこれらの同期状態を assertion にします。

changelog.d/unreleased/+readme-intro-cleanup.docs.md

@@ -0,0 +1,19 @@
+---
+category: docs
+affected:
+  - README.md
+  - USER_GUIDE.md
+  - DEVELOPER_GUIDE.md
+  - AGENT_GUIDE.md
+  - TESTING_GUIDE.md
+  - tests/CodeIndex.Tests/DocumentationStatusContractTests.cs
+  - tests/CodeIndex.Tests/LicensePolicyTests.cs
+---
+
+## English
+
+- Keep the bilingual README focused on an introduction, quick start, capabilities, documentation links, contribution policy, and license. Consolidate query, audit, indexing, and status details into existing user/developer guide sections, retain one badge block at the top, and align documentation checks with the linked references.
+
+## 日本語
+
+- README の日英双方を概要・導入・主な機能・ドキュメント案内・貢献方針・ライセンスに絞りました。検索・監査・索引・status の詳細を既存のユーザー／開発者ガイドへ統合し、バッジを冒頭の1組にまとめ、参照先に合わせてドキュメント検証を更新しました。

tests/CodeIndex.Tests/DocumentationStatusContractTests.cs

@@ -95,7 +95,6 @@ public class DocumentationStatusContractTests
     ];
 
     [Theory]
-    [InlineData("README.md")]
     [InlineData("DEVELOPER_GUIDE.md")]
     [InlineData("AGENT_GUIDE.md")]
     public void StatusContractDocs_MentionEveryTrustField(string relativePath)
@@ -108,4 +107,19 @@ public void StatusContractDocs_MentionEveryTrustField(string relativePath)
         }
     }
 
+    [Theory]
+    [InlineData("## Documentation", "# cdidx（日本語）", "status-json-contract", "#### Status JSON contract")]
+    [InlineData("## ドキュメント", "## コントリビューション方針", "status-json-契約", "#### Status JSON 契約")]
+    public void Readme_LinksToStatusContractInEachLanguage(
+        string sectionStart, string sectionEnd, string anchor, string targetHeading)
+    {
+        var readme = RepositoryTestPaths.ReadText("README.md");
+        var start = readme.IndexOf(sectionStart, StringComparison.Ordinal);
+        Assert.True(start >= 0);
+        var end = readme.IndexOf(sectionEnd, start, StringComparison.Ordinal);
+        Assert.True(end > start);
+        Assert.Contains($"(DEVELOPER_GUIDE.md#{anchor})", readme[start..end], StringComparison.Ordinal);
+        Assert.Contains(targetHeading, RepositoryTestPaths.ReadText("DEVELOPER_GUIDE.md"), StringComparison.Ordinal);
+    }
+
 }

tests/CodeIndex.Tests/LicensePolicyTests.cs

@@ -84,7 +84,7 @@ public void Readme_AdvertisesFairSourceLicenseInBothLanguageSections()
     {
         var readme = RepositoryTestPaths.ReadText("README.md");
 
-        Assert.Equal(2, CountOccurrences(readme, "License-FSL--1.1--ALv2-orange"));
+        Assert.Equal(1, CountOccurrences(readme, "License-FSL--1.1--ALv2-orange"));
         Assert.Contains("License and Fair Source Use", readme);
         Assert.Contains("ライセンスと Fair Source の扱い", readme);
         Assert.Equal(2, CountOccurrences(readme, "Fair Source-style software"));