Docs: Update version references to v0.26.0 in READMEs and docs (#15941)

### What problem does this PR solve?

- Update version tags in README files (including translations) from
v0.25.6 to v0.26.0
- Modify Docker image references and documentation to reflect new
version
- Update version badges and image descriptions
- Maintain consistency across all language variants of README files

### Type of change

- [x] Documentation Update

admin/client/README.md

@@ -48,7 +48,7 @@ It consists of a server-side Service and a command-line client (CLI), both imple
 1.  Ensure the Admin Service is running.
 2.  Install ragflow-cli.
     ```bash
-    pip install ragflow-cli==0.25.6
+    pip install ragflow-cli==0.26.0
     ```
 3.  Launch the CLI client:
     ```bash

admin/client/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "ragflow-cli"
-version = "0.25.6"
+version = "0.26.0"
 description = "Admin Service's client of [RAGFlow](https://github.com/infiniflow/ragflow). The Admin Service provides user management and system monitoring. "
 authors = [{ name = "Lynn", email = "lynn_inf@hotmail.com" }]
 license = { text = "Apache License, Version 2.0" }

admin/client/uv.lock

@@ -188,7 +188,7 @@ wheels = [
 
 [[package]]
 name = "ragflow-cli"
-version = "0.25.6"
+version = "0.26.0"
 source = { virtual = "." }
 dependencies = [
     { name = "beartype" },