El IDE: 10-round pass — syntax highlighting, file browser, runner, completion, split panes, find/replace, settings, minimap

Round 1: Fix dependency paths (../el/crates → ../el/engrams), verify build
Round 2: Enhanced syntax highlighting — function call detection, all El keywords (activate, sealed, parallel, deploy, etc.)
Round 3: Full El keyword set in CodeMirror tokenizer and completions; 50+ builtin function completions with type signatures
Round 4: File system integration — mkdir, rename, delete, file tree search; git status badges
Round 5: Runner integration — Ctrl+R shortcut, SSE streaming output, clickable error lines with jump-to-line
Round 6: Error highlighting with accurate line/col from lexer/parser spans; diagnostic dedup
Round 7: Find/replace panel; Ctrl+G go-to-line; toggle line comment; word-wrap compartment fix
Round 8: Code completion — 50+ builtins, keyword completions, snippet completions, server snippet integration
Round 9: Resizable panels — file tree drag-resize + collapse (Ctrl+B), type-graph drag-resize, bottom panel toggle (Ctrl+J), width persistence
Round 10: Settings API (GET/POST/DELETE /api/settings, ~/.el-ide/settings.json); frontend wired to API with debounced save; theme persistence
Round 11: Minimap click-to-jump and drag-to-scroll
Round 12: Command palette — added Go To Line, Toggle Word Wrap/Minimap/File Tree/Bottom Panel, font size commands, New File, Select Next Occurrence
Round 13: Multi-cursor — Ctrl+D select next occurrence, EditorSelection exposed for multi-range selection

crates/el-ide-server/Cargo.toml

@@ -27,6 +27,7 @@ tokio-stream        = { workspace = true }
 which               = { workspace = true }
 urlencoding         = "2"
 mime_guess          = { workspace = true }
+futures-util        = { workspace = true }
 
 [dev-dependencies]
 tokio       = { workspace = true, features = ["macros", "rt"] }