feat: add bulk user secret import endpoint and SDK client (PLAT-240) (#26724)

Adds `POST /api/v2/users/{user}/secrets/batch` and
`codersdk.Client.ImportUserSecrets` to import env, JSON, or YAML secrets
atomically. The endpoint validates each entry, rolls back the full batch
on conflicts or limits, omits secret values from responses and audit
logs, and imports keys that cannot be injected as environment variables
with an empty `env_name`.

Part of the [PLAT-240 bulk secret import
stack](https://linear.app/codercom/issue/PLAT-240). Reviewed and updated
by Coder Agents on behalf of @dylanhuff-at-coder.

docs/reference/api/schemas.md

@@ -7912,6 +7912,22 @@ Only certain features set these fields: - FeatureManagedAgentLimit|
 | `refresh`            | integer | false    |              |             |
 | `threshold_database` | integer | false    |              |             |
 
+## codersdk.ImportUserSecretsRequest
+
+```json
+{
+  "content": "string",
+  "format": "env"
+}
+```
+
+### Properties
+
+| Name      | Type                                                     | Required | Restrictions | Description |
+|-----------|----------------------------------------------------------|----------|--------------|-------------|
+| `content` | string                                                   | true     |              |             |
+| `format`  | [codersdk.SecretsFileFormat](#codersdksecretsfileformat) | true     |              |             |
+
 ## codersdk.InboxNotification
 
 ```json
@@ -11374,6 +11390,20 @@ Only certain features set these fields: - FeatureManagedAgentLimit|
 | `ssh_config_options` | object | false    |              |                                                                                                                       |
 | » `[any property]`   | string | false    |              |                                                                                                                       |
 
+## codersdk.SecretsFileFormat
+
+```json
+"env"
+```
+
+### Properties
+
+#### Enumerated Values
+
+| Value(s)              |
+|-----------------------|
+| `env`, `json`, `yaml` |
+
 ## codersdk.ServerSentEvent
 
 ```json

docs/reference/api/secrets.md

@@ -117,6 +117,80 @@ curl -X POST http://coder-server:8080/api/v2/users/{user}/secrets \
 
 To perform this operation, you must be authenticated. [Learn more](authentication.md).
 
+## Import user secrets from a file
+
+### Code samples
+
+```sh
+# Example request using curl
+curl -X POST http://coder-server:8080/api/v2/users/{user}/secrets/batch \
+  -H 'Content-Type: application/json' \
+  -H 'Accept: application/json' \
+  -H 'Coder-Session-Token: API_KEY'
+```
+
+`POST /api/v2/users/{user}/secrets/batch`
+
+> Body parameter
+
+```json
+{
+  "content": "string",
+  "format": "env"
+}
+```
+
+### Parameters
+
+| Name   | In   | Type                                                                             | Required | Description              |
+|--------|------|----------------------------------------------------------------------------------|----------|--------------------------|
+| `user` | path | string                                                                           | true     | User ID, username, or me |
+| `body` | body | [codersdk.ImportUserSecretsRequest](schemas.md#codersdkimportusersecretsrequest) | true     | Import secrets request   |
+
+### Example responses
+
+> 201 Response
+
+```json
+[
+  {
+    "created_at": "2019-08-24T14:15:22Z",
+    "description": "string",
+    "env_name": "string",
+    "file_path": "string",
+    "id": "497f6eca-6276-4993-bfeb-53cbbbba6f08",
+    "name": "string",
+    "updated_at": "2019-08-24T14:15:22Z"
+  }
+]
+```
+
+### Responses
+
+| Status | Meaning                                                                 | Description              | Schema                                                        |
+|--------|-------------------------------------------------------------------------|--------------------------|---------------------------------------------------------------|
+| 201    | [Created](https://tools.ietf.org/html/rfc7231#section-6.3.2)            | Created                  | array of [codersdk.UserSecret](schemas.md#codersdkusersecret) |
+| 400    | [Bad Request](https://tools.ietf.org/html/rfc7231#section-6.5.1)        | Bad Request              | [codersdk.Response](schemas.md#codersdkresponse)              |
+| 409    | [Conflict](https://tools.ietf.org/html/rfc7231#section-6.5.8)           | Conflict                 | [codersdk.Response](schemas.md#codersdkresponse)              |
+| 413    | [Payload Too Large](https://tools.ietf.org/html/rfc7231#section-6.5.11) | Request Entity Too Large | [codersdk.Response](schemas.md#codersdkresponse)              |
+
+<h3 id="import-user-secrets-from-a-file-responseschema">Response Schema</h3>
+
+Status Code **201**
+
+| Name            | Type              | Required | Restrictions | Description |
+|-----------------|-------------------|----------|--------------|-------------|
+| `[array item]`  | array             | false    |              |             |
+| `» created_at`  | string(date-time) | false    |              |             |
+| `» description` | string            | false    |              |             |
+| `» env_name`    | string            | false    |              |             |
+| `» file_path`   | string            | false    |              |             |
+| `» id`          | string(uuid)      | false    |              |             |
+| `» name`        | string            | false    |              |             |
+| `» updated_at`  | string(date-time) | false    |              |             |
+
+To perform this operation, you must be authenticated. [Learn more](authentication.md).
+
 ## Get a user secret by name
 
 ### Code samples