chore: adopt remote dprint config, tidy examples

Extend dprint from a shared remote config and add the prettier
and exec plugins, formatting TOML via a new tombi.toml instead
of golangci-lint fmt. Taskfile.yml, scripts/build.sh, and
html_styles.css pick up the resulting reformat.

Exporter examples now write to a temp dir and clean up after
themselves instead of leaving output.md/.docx/.html in the
repo. Drop the stray internal/exporters/output.docx and ignore
internal/exporters/output.* going forward.

internal/exporters/html_styles.css

@@ -1,7 +1,13 @@
 body {
 	font-family:
-		-apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu,
-		Cantarell, sans-serif;
+		-apple-system,
+		BlinkMacSystemFont,
+		"Segoe UI",
+		Roboto,
+		Oxygen,
+		Ubuntu,
+		Cantarell,
+		sans-serif;
 	line-height: 1.6;
 	color: #333;
 	max-width: 800px;