feat: add output truncation and offset paging to all large-output tools

- coding_tools: list_files (max_entries=200, sorted), run_command
  (max_chars=8000, output_offset), grep_search (max_lines=100, offset);
  added _truncate_output helper for run_command paging
- pr_tools: get_pull_request_diff / get_pull_request_patch now truncate
  at 15k chars with hunk-boundary awareness and char_offset paging;
  get_pull_request_comments gains limit/offset paging
- issue_tools: get_issue_comments gains limit/offset paging
- file_tools: get_file_content / get_file_content_with_ref now paginate
  by line (offset=1, limit=250), matching existing read_file convention;
  added _paginate_lines helper
- research_tools: fetch_url gains char_offset parameter; _smart_truncate
  now slices from an offset and embeds next char_offset in the footer
- gitea_tools facade: all new params threaded through

gitea/tools/file_tools.py

@@ -8,21 +8,74 @@ class FileTools:
     def __init__(self, client: GiteaClient) -> None:
         self._client = client
 
-    def get_file_content(self, owner: str, repo: str, path: str) -> str:
+    def _paginate_lines(
+        self,
+        content: str,
+        offset: int,
+        limit: int,
+    ) -> str:
+        """Return lines[offset-1 : offset-1+limit] with a paging footer if truncated.
+
+        Uses the same 1-indexed convention as CodingTools.read_file.
+        """
+        lines: list[str] = content.splitlines()
+        total: int = len(lines)
+        start: int = offset - 1  # convert to 0-indexed
+        page: list[str] = lines[start : start + limit]
+        formatted: list[str] = [
+            f"{start + i + 1}: {line}" for i, line in enumerate(page)
+        ]
+        result: str = "\n".join(formatted)
+        end_line: int = start + len(page)
+        if end_line < total:
+            next_offset: int = end_line + 1
+            result += (
+                f"\n\n[{total} lines total — showing lines {offset}–{end_line}. "
+                f"Re-call with offset={next_offset} to read more.]"
+            )
+        return result
+
+    def get_file_content(
+        self,
+        owner: str,
+        repo: str,
+        path: str,
+        offset: int = 1,
+        limit: int = 250,
+    ) -> str:
+        """Get the content of a file from a Gitea repository with line paging.
+
+        Args:
+            offset: 1-indexed line to start from (default 1).
+            limit: Maximum number of lines to return (default 250).
+        """
         try:
             content = self._client.get_file_content(owner, repo, path)
-            if isinstance(content, list):
-                return "\n".join(content)
-            return content
+            raw: str = "\n".join(content) if isinstance(content, list) else content
+            return self._paginate_lines(raw, offset, limit)
         except Exception as e:
             return f"Error getting file content: {str(e)}"
 
-    def get_file_content_with_ref(self, owner: str, repo: str, path: str, ref: str = "master") -> str:
+    def get_file_content_with_ref(
+        self,
+        owner: str,
+        repo: str,
+        path: str,
+        ref: str = "master",
+        offset: int = 1,
+        limit: int = 250,
+    ) -> str:
+        """Get file content at a specific git ref with line paging.
+
+        Args:
+            ref: Branch, tag, or commit SHA (default 'master').
+            offset: 1-indexed line to start from (default 1).
+            limit: Maximum number of lines to return (default 250).
+        """
         try:
             content = self._client.get_file_content(owner, repo, path, ref)
-            if isinstance(content, list):
-                return "\n".join(content)
-            return content
+            raw: str = "\n".join(content) if isinstance(content, list) else content
+            return self._paginate_lines(raw, offset, limit)
         except Exception as e:
             return f"Error getting file content: {str(e)}"