ref-docs: changefeedccl: support CREATE DATABASE CHANGEFEED syntax

src/current/v26.1/create-changefeed-database.md

@@ -0,0 +1,62 @@
+---
+title: changefeedccl: support CREATE DATABASE CHANGEFEED syntax
+summary: [HUMAN REVIEW: Feature Not Ready for Documentation]
+toc: true
+docs_area: reference
+---
+
+## [HUMAN REVIEW: Feature Not Ready for Documentation]
+
+**Issue**: This PR adds parsing support for `CREATE CHANGEFEED FOR DATABASE` syntax, but the feature is explicitly not implemented:
+
+1. **Release note**: "(none)" - indicating this isn't user-facing yet
+2. **Go code**: Returns `errors.UnimplementedError(errors.IssueLink{}, "database-level changefeed is not implemented")`
+3. **PR description**: "This PR only allows the aforementioned statement to be parsed; no changefeed is created"
+
+**Recommendation**: This appears to be preparatory work for a future feature. Documentation should wait until the feature is actually implemented and has a proper release note.
+
+---
+
+## Partial Reference Documentation (If Needed for Future Use)
+
+If you need to prepare documentation structure for when this feature becomes available, here's what I can derive from the syntax changes:
+
+### `CREATE CHANGEFEED` (Database-Level) - [NOT IMPLEMENTED]
+
+**Synopsis**:
+```
+CREATE CHANGEFEED FOR DATABASE database_name 
+    [INTO sink] 
+    [WITH option = value [, ...]]
+```
+
+**Description**: [NEEDS REVIEW] Creates a changefeed that captures changes for all tables within a specified database. This appears to be an extension of the existing table-level changefeed functionality to operate at the database scope.
+
+**Parameters**:
+
+| Parameter | Description | Required |
+| --- | --- | --- |
+| `database_name` | name of the database to monitor for changes | Yes |
+| `sink` | destination for changefeed output | No |
+| `option` | changefeed configuration options | No |
+
+**Current Status**: 
+{{site.data.alerts.callout_danger}}
+This syntax is not currently implemented and will return an error. The feature is under development as part of [CRDB-1421](https://cockroachlabs.atlassian.net/browse/CRDB-1421).
+{{site.data.alerts.end}}
+
+**Examples**:
+[NEEDS REVIEW - Examples cannot be tested as feature is not implemented]
+
+{% include_cached copy-clipboard.html %}
+~~~ sql
+CREATE CHANGEFEED FOR DATABASE mydb;
+~~~
+
+**See also**:
+- [`CREATE CHANGEFEED`]({% link {{ page.version.version }}/create-changefeed.md %}) (table-level)
+- [`ALTER CHANGEFEED`]({% link {{ page.version.version }}/alter-changefeed.md %})
+
+---
+
+**Recommendation**: Hold this documentation until the feature is implemented and ready for user consumption.