ai(rules[AGENTS]) Unify code block rules

why: Code block guidance drifted into four variants
across repos.

what:
- Merge the code block and shell command sections
- Lead with the paste-and-run contract

Author: tony

AGENTS.md

@@ -437,72 +437,38 @@ EOF
 
 ## Documentation Standards
 
-### Code Blocks in Documentation
-
-When writing documentation (README, CHANGES, docs/), follow these rules for code blocks:
-
-**One command per code block.** This makes commands individually copyable. For sequential commands, either use separate code blocks or chain them with `&&` or `;` and `\` continuations (keeping it one logical command).
-
-**Put explanations outside the code block**, not as comments inside.
+### Code Blocks
+
+Code blocks are paste-and-run units: pasting one block runs exactly one
+intended action. Doctests and other executed examples are exempt — the test
+suite runs them, nobody pastes them.
+
+- **One command per block.** Multiple steps may share a block only when
+  explicitly chained with `&&`, `;`, or `\` continuations — the chain is
+  then one logical command.
+- **Explanations go in prose above the block**, never as `#` comments inside it.
+- **Command menus are per-command blocks with prose lead-ins**, not tables.
+- **Shell commands use the `console` tag with a `$ ` prefix.** This separates
+  interactive commands from scripts and enables prompt-aware copy.
+- **Split long commands with `\`** — one flag or flag+value pair per indented
+  continuation line, positional arguments last.
 
 Good:
 
-Run the tests:
-
-```console
-$ uv run pytest
-```
-
-Run with coverage:
-
-```console
-$ uv run pytest --cov
-```
-
-Bad:
-
-```console
-# Run the tests
-$ uv run pytest
-
-# Run with coverage
-$ uv run pytest --cov
-```
-
-### Shell Command Formatting
-
-These rules apply to shell commands in documentation (README, CHANGES, docs/), **not** to Python doctests.
-
-**Use `console` language tag with `$ ` prefix.** This distinguishes interactive commands from scripts and enables prompt-aware copy in many terminals.
-
-Good:
-
-```console
-$ uv run pytest
-```
-
-Bad:
-
-```bash
-uv run pytest
-```
-
-**Split long commands with `\` for readability.** Each flag or flag+value pair gets its own continuation line, indented. Positional parameters go on the final line.
-
-Good:
+Show the last ten commits as a graph:
 
 ```console
-$ pipx install \
-    --suffix=@next \
-    --pip-args '\--pre' \
-    --force \
-    'libvcs'
+$ git log \
+    --max-count=10 \
+    --graph \
+    --oneline
 ```
 
 Bad:
 
 ```console
-$ pipx install --suffix=@next --pip-args '\--pre' --force 'libvcs'
+# Show the last ten commits as a graph
+$ git log --max-count=10 --graph --oneline
 ```
 
 ### Changelog Conventions