docs(code_security): document the secrets configuration file (DataDog#39313)

Adds the secrets.global-config fields to the Secret Scanning page and
schema-version v1.5 to the Code Security configuration reference.

Refs: K9CODESEC-4729

Author: MikaYuoadas

hugo/config/_default/menus/main.en.yaml

@@ -8077,7 +8077,7 @@ menu:
       url: /security/code_security/secret_scanning/generic_ci_providers/
       parent: sec_secret_scanning
       weight: 2
-    - name: Rule Configuration
+    - name: Configuration
       identifier: sec_secret_scanning_configuration
       url: /security/code_security/secret_scanning/configuration/
       parent: sec_secret_scanning

hugo/content/en/security/code_security/guides/configuration.md

@@ -12,6 +12,9 @@ further_reading:
 - link: /security/code_security/iac_security/configuration/
   tag: Documentation
   text: Infrastructure as Code (IaC) Security Configuration
+- link: /security/code_security/secret_scanning/configuration/
+  tag: Documentation
+  text: Secret Scanning Configuration
 ---
 
 Datadog Code Security can be configured in Datadog, in a file at the root of your repository, or in both locations.
@@ -27,22 +30,25 @@ The configuration file must begin with a `schema-version` key, followed by top-l
 | `v1.2` | SAST, SCA, IaC Security |
 | `v1.3` | SAST, SCA, IaC Security |
 | `v1.4` | SAST, SCA, IaC Security |
+| `v1.5` | SAST, SCA, IaC Security, Secret Scanning |
 
-Use `schema-version: v1.4` for all new configurations. It supports the same products as `v1.3` and adds per-rule `arguments` for IaC rules. Version `v1.3` added IaC configuration options such as per-rule path scoping, per-rule severity overrides, and platform filters. See [Infrastructure as Code (IaC) Security Configuration][3] for IaC-specific fields.
+Use `schema-version: v1.5` for all new configurations. It supports the same products as `v1.4` and adds Secret Scanning. Version `v1.4` added per-rule `arguments` for IaC rules, and `v1.3` added IaC configuration options such as per-rule path scoping, per-rule severity overrides, and platform filters. See [Infrastructure as Code (IaC) Security Configuration][3] for IaC-specific fields and [Secret Scanning Configuration][4] for secrets-specific fields.
 
 The following example shows the top-level structure:
 
 ```yaml
-schema-version: v1.4
+schema-version: v1.5
 sast:
   # Static Code Analysis (SAST) configuration
 sca:
   # Software Composition Analysis (SCA) configuration
 iac:
   # Infrastructure as Code (IaC) Security configuration
+secrets:
+  # Secret Scanning configuration
 ```
 
-The `sast`, `sca`, and `iac` sections are optional. Any configuration location, including the org level, repository level, or repository file, can include one or more sections. The `sast` section also controls AI-native SAST rulesets for Datadog-hosted scans. For the full schema for each section and AI-native SAST ruleset names, see [Static Code Analysis (SAST) Configuration][1], [Software Composition Analysis (SCA) Configuration][2], and [Infrastructure as Code (IaC) Security Configuration][3].
+The `sast`, `sca`, `iac`, and `secrets` sections are optional. Any configuration location, including the org level, repository level, or repository file, can include one or more sections. The `sast` section also controls AI-native SAST rulesets for Datadog-hosted scans. The `secrets` section controls which files are scanned for secrets; the rules themselves are configured in Datadog. For the full schema for each section, see [Static Code Analysis (SAST) Configuration][1], [Software Composition Analysis (SCA) Configuration][2], [Infrastructure as Code (IaC) Security Configuration][3], and [Secret Scanning Configuration][4]. The SAST page also lists the AI-native SAST ruleset names.
 
 ## Where to define configurations
 
@@ -195,3 +201,4 @@ The example demonstrates each merge rule from the table above:
 [1]: /security/code_security/static_analysis/configuration/
 [2]: /security/code_security/software_composition_analysis/configuration/
 [3]: /security/code_security/iac_security/configuration/
+[4]: /security/code_security/secret_scanning/configuration/

hugo/content/en/security/code_security/secret_scanning/configuration.md

@@ -1,11 +1,13 @@
 ---
-title: Rule Configuration
+title: Configuration
 algolia:
   tags: ['static analysis', 'ci pipeline', 'SAST', 'secret scanning']
-description: Configure rules for Datadog Secret Scanning, including managed default rules and custom regex rules.
+description: Configure Datadog Secret Scanning rules and the files that are scanned.
 ---
 
 By default, Datadog Secret Scanning scans enabled repositories with all [rules in the Secrets & Credentials category of Sensitive Data Scanner][1]. You can customize which rules run, modify default rules, and create custom rules on the [{{< ui >}}Code{{< /ui >}} configuration page][2] in SDS.
+
+The rules, scanning groups, and custom rules described on this page are configured in Datadog. A configuration file in your repository adds separate control over which files are scanned. See [File configuration](#file-configuration).
 ## Scanning groups
 There are two scanning groups that configure Secret Scanning rules.
 ### Managed scanning group
@@ -44,6 +46,42 @@ Disable a rule by clicking the blue toggle on the right.
 
 <div class="alert alert-info">After a specific rule is disabled, existing findings from that rule are auto-closed in Secret Scanning on the next commit.</div>
 
+## File configuration
+
+Rules are configured in Datadog as described in the [Configuring rules](#configuring-rules) section. Which files Secret Scanning reads is configured under the `secrets` key in the Code Security configuration. Define it in Datadog, or in a `code-security.datadog.yaml` file at the root of your repository.
+
+For information on configuration locations, precedence, and merging, see [Code Security Configuration Reference][4].
+
+The configuration must begin with `schema-version: v1.5`, followed by a `secrets` key containing a `global-config` object. The `global-config` object controls repository-wide settings:
+
+| **Property** | **Type** | **Description** | **Default** |
+| --- | --- | --- | --- |
+| `only-paths` | Array | File paths or glob patterns. Only matching files are analyzed. | None |
+| `ignore-paths` | Array | File paths or glob patterns to exclude. Matching files are not analyzed. | None |
+| `use-gitignore` | Boolean | Whether to include entries from the `.gitignore` file in `ignore-paths`. | `true` |
+| `ignore-generated-files` | Boolean | Whether to include common generated file patterns in `ignore-paths`. | `true` |
+| `max-file-size-kb` | Number | Maximum file size (in kB) to analyze. Larger files are ignored. | `10240` |
+
+### Example configuration
+
+{{< code-block lang="yaml" >}}
+schema-version: v1.5
+secrets:
+  global-config:
+    # Only analyze the following paths/files
+    only-paths:
+      - "src"
+      - "**/*.py"
+    # Do not analyze the following paths/files
+    ignore-paths:
+      - "tests"
+      - "**/*.lock"
+    use-gitignore: true
+    ignore-generated-files: true
+    max-file-size-kb: 10240
+{{< /code-block >}}
+
 [1]: /security/sensitive_data_scanner/scanning_rules/library_rules/?category=Secrets+and+credentials
 [2]: https://app.datadoghq.com/sensitive-data-scanner/configuration/code
 [3]: /security/sensitive_data_scanner/scanning_rules/custom_rules/
+[4]: /security/code_security/guides/configuration/