feat: implement phases 3-5 of Arma 3 UX enhancement plan

Phase 3 - Mod display names + split-pane selector:
- Parse mod.cpp/meta.cpp for display_name and workshop_id
- Rewrite ModList as two-pane available/selected interface

Phase 4 - Player kick/ban from Players tab:
- Add get_by_slot() to PlayerRepository
- Add get_rcon_client() class method to ThreadRegistry
- Add /players/{slot_id}/kick and /ban endpoints
- Rewrite PlayerTable with kick/ban modals and ban presets

Phase 5 - Historical log file browser:
- Add list_log_files() and get_log_file_path() to RPTParser
- Add logfiles_router with GET/download/DELETE endpoints
- Update LogViewer with collapsible log files section (download + delete)

backend/adapters/arma3/log_parser.py

@@ -62,6 +62,36 @@ class RPTParser:
             "message": (message or "").strip(),
         }
 
+    def list_log_files(self, server_dir: Path) -> list[dict]:
+        """Return all .rpt log files in server_dir/server/, newest first."""
+        profile_dir = server_dir / "server"
+        if not profile_dir.exists():
+            return []
+        files = []
+        for p in profile_dir.glob("*.rpt"):
+            try:
+                stat = p.stat()
+                files.append({
+                    "filename": p.name,
+                    "size_bytes": stat.st_size,
+                    "modified_at": stat.st_mtime,
+                })
+            except OSError:
+                pass
+        files.sort(key=lambda f: f["modified_at"], reverse=True)
+        return files
+
+    def get_log_file_path(self, server_dir: Path, filename: str) -> Path | None:
+        """Return the Path for a specific log file, or None if not found / path traversal attempt."""
+        import os
+        profile_dir = server_dir / "server"
+        target = (profile_dir / filename).resolve()
+        if not str(target).startswith(str(profile_dir.resolve())):
+            return None
+        if not target.exists() or target.suffix != ".rpt":
+            return None
+        return target
+
     def get_log_file_resolver(self, server_id: int) -> Callable[[Path], Path | None]:
         """Return a callable that finds the current RPT log file."""
         def resolver(server_dir: Path) -> Path | None: