feat(docs-site): syntax-highlight examples and restyle the site

The manual is authored man-page style: every synopsis, example, option
table, and description sits in one 4-space-indented block. On the site
that renders as a single unhighlighted grey slab, because an indented
block declares no language.

Split each block into its paragraphs at site-build time and classify
them: synopsis and shell examples become ```fish fences, descriptions
become real prose, and column-aligned reference tables keep their
indentation. 175 blocks now highlight; the 412 lines of genuine tables
are left alone.

The transform is site-only. docs/manual/** keeps the indented form the
pandoc man-page pipeline and config-help depend on, and a test enforces
that no fence is ever written back to the SSOT.

Also:
- Point Expressive Code at the bundled Catppuccin Mocha/Latte themes so
  code blocks match the palette in catppuccin.css.
- Build the functions sidebar group explicitly. `autogenerate` labelled
  it with the raw directory slug and republished the directory index as
  a child of the group it already titled, producing the duplicate
  "Functions Reference" row.
- Skip `Synopsis:` lines when deriving card descriptions; they restated
  the calling convention the card already shows as its title.
- Widen the palette: tinted heading levels, inline code, links, card
  hover accents, aside accents, and table headers.

Fixes a bug where _split_entries stripped the leading indentation of an
entry's first line, detaching `Synopsis:` from the block it opens.

docs/verify-manual.py

@@ -213,6 +213,86 @@ def test_site_build_produces_function_pages():
             assert "title" in fm, f"{page.name} has no title"
 
 
+def test_prettify_splits_an_entry_block():
+    """A man-page-style entry becomes fenced code, prose, and a table."""
+    import build_manual
+
+    body = "\n".join(
+        [
+            "    Synopsis:  rm [-e | args...]",
+            "    Safe rm wrapper routing to trash:",
+            "",
+            "      (no args)   List current trash contents",
+            "      -e/--empty  Empty the trash",
+            "",
+            "    Falls back to /usr/bin/rm when trash is unavailable.",
+            "",
+            "    rm file.txt           # moves to trash",
+            "    rm -e                 # empty trash",
+        ]
+    )
+    out = build_manual.prettify(body, "rm")
+
+    assert "```fish\nrm [-e | args...]\n```" in out, "synopsis was not fenced as fish"
+    assert "```fish\nrm file.txt" in out, "examples were not fenced as fish"
+    assert out.count("```") == 4, f"expected exactly two fences, got:\n{out}"
+    assert "\nSafe rm wrapper routing to trash:" in out, "description stayed indented"
+    assert (
+        "\n      (no args)   List current trash contents" in out
+    ), "option table lost its indentation"
+    assert (
+        "\nFalls back to /usr/bin/rm when trash is unavailable." in out
+    ), "trailing prose stayed indented"
+
+
+def test_prettify_leaves_reference_tables_alone():
+    """Column-aligned blocks are data, not shell, and must not be fenced."""
+    import build_manual
+
+    table = "    XDG_CONFIG_HOME    ~/.config\n    XDG_CACHE_HOME     ~/.cache"
+    assert "```" not in build_manual.prettify(table), "a reference table got fenced"
+
+    binds = "    n / nv / neovim    nvim\n    e                  edit"
+    assert "```" not in build_manual.prettify(binds), "an abbreviation table got fenced"
+
+    shell = "    set -U __fish_user_dots_path /path/to/dots"
+    assert "```fish" in build_manual.prettify(shell), "a shell block was not fenced"
+
+
+def test_prettify_is_site_only():
+    """The SSOT keeps the indented form the man-page pipeline depends on."""
+    import build_manual
+
+    manual = Path(__file__).parent / "manual"
+    for path in manual.rglob("*.md"):
+        assert "```" not in path.read_text(), (
+            f"{path.name} contains a fence: prettify must run at site-build "
+            "time, never be written back to the SSOT"
+        )
+
+
+def test_sidebar_has_no_duplicate_functions_entry():
+    """The functions group must not also list itself as one of its children."""
+    import build_manual
+
+    docs = Path(__file__).parent
+    with tempfile.TemporaryDirectory() as d:
+        sidebar = build_manual.build_site(docs / "manual", Path(d))
+
+    groups = [e for e in sidebar if "items" in e]
+    assert len(groups) == 1, f"expected one sidebar group, got {len(groups)}"
+    group = groups[0]
+    labels = [item["label"] for item in group["items"]]
+    assert group["label"] not in labels[1:], (
+        f"'{group['label']}' is repeated inside its own group: {labels}"
+    )
+    assert labels[0] == "Overview", f"group should lead with Overview, got {labels[0]}"
+    assert not any(
+        "autogenerate" in item for item in group["items"]
+    ), "categories should be listed explicitly, not autogenerated from slugs"
+    assert len(labels) == 15, f"expected Overview + 14 categories, got {len(labels)}"
+
+
 TESTS = [v for k, v in sorted(globals().items()) if k.startswith("test_")]