feat: surface inline-comment anchor fields on pr view --reviews (task 0034)

Each inline review comment under `pr view <n> --reviews` now renders its
`id` (the handle a reply targets), `resolved` (`yes`/`no`, from whether
Gitea populated the comment's `resolver`), and `diff_hunk`. The hunk is
structurally trimmed to its `@@` header line plus its last two lines by
default (hunks of three lines or fewer are left whole) and emitted
verbatim under `--full`, so the trim never touches the char-based body
truncation path. The raw `position`/`original_position` diff offsets stay
unsurfaced. The fields ride the existing reviews-plus-per-review-comments
fetch — no extra API calls.

src/diff.ts

@@ -56,3 +56,20 @@ export function truncateDiff(diff: string, full: boolean): DiffResult {
     original_length: diff.length,
   };
 }
+
+/**
+ * Structurally trim a review comment's `diff_hunk` to its anchor: the `@@`
+ * header line plus the hunk's last two lines. A hunk of three lines or fewer is
+ * already covered by that (header + last two), so it is returned unchanged.
+ *
+ * This is deliberately not the char-based body truncation: it keeps both the
+ * file-line anchor (the `@@` header) and the code at the comment (the tail),
+ * which a keep-head char truncation would get backwards by dropping the tail.
+ */
+export function trimDiffHunk(hunk: string): string {
+  const lines = hunk.split("\n");
+  if (lines.length <= 3) {
+    return hunk;
+  }
+  return [lines[0], ...lines.slice(-2)].join("\n");
+}