docs(style[shell]): Standardize shell code blocks in docs

why: Improve copy-pastability and readability of shell examples
what:
- Ensure all shell blocks use console tag with $ prefix
- Fix README.md installation examples
- Fix CHANGES shell examples

Author: tony

CHANGES

@@ -393,14 +393,14 @@ _Maintenance only, no bug fixes, or new features_
 
   via ruff v0.3.4, all automated lint fixes, including unsafe and previews were applied:
 
-  ```sh
-  ruff check --select ALL . --fix --unsafe-fixes --preview --show-fixes; ruff format .
+  ```console
+  $ ruff check --select ALL . --fix --unsafe-fixes --preview --show-fixes; ruff format .
   ```
 
   Branches were treated with:
 
-  ```sh
-  git rebase \
+  ```console
+  $ git rebase \
       --strategy-option=theirs \
       --exec 'poetry run ruff check --select ALL . --fix --unsafe-fixes --preview --show-fixes; poetry run ruff format .; git add src tests; git commit --amend --no-edit' \
       origin/master

README.md

@@ -26,20 +26,20 @@ It powers [vcspull](https://github.com/vcs-python/vcspull) and simplifies VCS in
 
 ## Installation
 
-```bash
-pip install libvcs
+```console
+$ pip install libvcs
 ```
 
 With [uv](https://docs.astral.sh/uv/):
 
-```bash
-uv add libvcs
+```console
+$ uv add libvcs
 ```
 
 Try it interactively:
 
-```bash
-uvx --with libvcs ipython
+```console
+$ uvx --with libvcs ipython
 ```
 
 Tip: libvcs is pre-1.0. Pin a version range in projects to avoid surprises: