docs: add caution when reading readme

Author: yaadata

README.md

@@ -10,6 +10,12 @@ Neovim plugin for running the Codex CLI in an embedded terminal.
 - Neovim >= 0.11.0
 - `codex` available on your `PATH` (or configure `cmd`)
 
+> [!CAUTION]
+> You are reading the `master` branch README. Install and configuration details
+> may differ from tagged releases. The current latest release tag is `v0.2.1`.
+> For version-accurate instructions, read the README for your target tag from
+> [Codeberg releases](https://codeberg.org/yaadata/codex.nvim/releases).
+
 ## Install
 
 ```lua

docs/contributing.md

@@ -327,6 +327,14 @@ docs(project): add LICENSE file
 test(core): add resume dual-mode behavior tests
 ```
 
+### Release Docs Checklist
+
+When cutting a new release tag:
+
+1. Update the warning banner in `README.md` to state the new latest tag.
+2. Verify the release reference points to
+   `https://codeberg.org/yaadata/codex.nvim/releases`.
+
 ## Adding a New Command
 
 1. **API function** -- Add the public method in `lua/codex/init.lua` with