fix(rest): keep a text hyperlink's destination whole on import (#459)

A hyperlink longer than 200 characters came back as a different 200-character
URL -- one that still looks like a working link -- and the import reported
nothing. It applied to a text layer's base style and to a character style
override alike.

The destination went through `clip_str`, which exists so that names and labels
from a file stay readable when they are quoted in a warning. Every other caller
is a name, a description, a style id or a layer type; a hyperlink is data, and
clipping it silently rewrote it. Two things say so: the FIG importer already
keeps the URL whole, so the two importers disagreed, and `rest::props` bounds
numbers and list lengths but no string beyond that label helper -- the text
content itself is not clipped either.

The reporter's integration test is included, with its assertions unchanged. Its
helper is restructured to return what it found rather than unwrap: the crate
denies `unwrap_used` and `panic`, and `clippy.toml` allows them only inside a
`#[test]` function, so the original shape failed the gate before it ran. Its
failure message now reports the input and output lengths.

crates/format/tests/import_link_contract.rs

@@ -0,0 +1,57 @@
+//! A text hyperlink's destination survives a REST import whole, however long it is (#459).
+//!
+//! The assertions are the reporter's; the helper returns its findings instead of unwrapping, so
+//! that the crate's `unwrap_used`/`panic` lints hold outside a `#[test]` function.
+
+use figcraft_doc::NodeKind;
+use figcraft_format::rest;
+use serde_json::json;
+
+/// The link of the imported text, and the warnings the import reported. `None` for a link means
+/// the layer was missing, was not text, or carried no link at all.
+fn imported_link(length: usize, override_style: bool) -> (String, Option<String>, Vec<String>) {
+    let url = format!("https://example.com/{}", "a".repeat(length - 20));
+    assert_eq!(url.len(), length);
+    let mut text = json!({"id":"1:2","type":"TEXT","name":"Link","characters":"A","relativeTransform":[[1,0,0],[0,1,0]]});
+    let style = json!({"hyperlink":{"type":"URL","url":url}});
+    if override_style {
+        text["characterStyleOverrides"] = json!([1]);
+        text["styleOverrideTable"] = json!({"1":style});
+    } else {
+        text["style"] = style;
+    }
+    let input = json!({"document":{"type":"DOCUMENT","children":[{"id":"1:1","type":"CANVAS","children":[text]}]}});
+    assert!(rest::is_rest_json(&input));
+    let Ok((doc, warnings)) = rest::import(&input, &rest::no_images) else {
+        return (url, None, vec!["import failed".into()]);
+    };
+    let link = match doc.nodes().find(|n| n.name == "Link").map(|n| &n.kind) {
+        Some(NodeKind::Text(data)) if override_style => data.runs.first().and_then(|r| r.style.link.clone()),
+        Some(NodeKind::Text(data)) => data.style.link.clone(),
+        _ => None,
+    };
+    (url, link, warnings)
+}
+
+/// Every length in turn: the destination comes back exactly, and nothing is reported.
+fn check(override_style: bool) {
+    let mut mismatches = Vec::new();
+    for length in [200, 201, 240] {
+        let (url, link, warnings) = imported_link(length, override_style);
+        assert!(warnings.is_empty(), "import warned at {length}: {warnings:?}");
+        if link.as_deref() != Some(url.as_str()) {
+            mismatches.push((length, link.map_or(0, |l| l.len())));
+        }
+    }
+    assert!(mismatches.is_empty(), "URLs changed, (input length, output length): {mismatches:?}");
+}
+
+#[test]
+fn base_hyperlink_preserves_url() {
+    check(false);
+}
+
+#[test]
+fn override_hyperlink_preserves_url() {
+    check(true);
+}