Update copilot instructions

Author: celonymire

.github/instructions/extension-backend.instructions.md

@@ -10,28 +10,50 @@ applyTo: "src/extension/**/*.ts"
 
 ## File Persistence Lifecycle
 
-Both Judge and Stress implement the same file-switching pattern:
+Both Judge and Stress implement the same file-switching pattern defined in `BaseViewProvider`:
 
 1. `loadCurrentFileData()` is the entry point when the webview becomes visible
 2. `_ensureActiveEditorListener()` subscribes to editor changes
-3. `_handleActiveEditorChange()` filters non-file schemes and calls `_switchToFile()`
-4. `_switchToFile(file)` loads persisted data from workspaceState, creates in-memory state, and rehydrates the webview
-5. `_switchToNoFile()` handles cases where no valid file is open
-6. `_rehydrateWebviewFromState()` sends current in-memory state to the webview
+3. `_handleActiveEditorChange()` filters non-file/untitled schemes and calls `_switchToFile()`
+4. `_syncOrSwitchToTargetFile()` decides between rehydrating the current file or switching:
+   - Same file with existing state → `_rehydrateWebviewFromState()`
+   - Different file → `_switchToFile(file)`
+   - No file → `_sendShowMessage(false)`
+5. `_switchToFile(file)` loads persisted data from workspaceState, creates in-memory state, and rehydrates the webview
+6. `_switchToNoFile()` handles cases where no valid file is open
+7. `_rehydrateWebviewFromState()` sends current in-memory state to the webview
+
+Subclasses must implement these abstract methods:
+
+- `_switchToFile(file)` / `_switchToNoFile()` / `_rehydrateWebviewFromState()` / `_sendShowMessage(visible)`
+- `_hasState()`: Override to control same-file rehydration (e.g., Judge checks `_runtime.state.length > 0`)
 
 When switching files, processes are **not** stopped. Instead, they are moved to the background (e.g., via `_moveCurrentStateToBackground`) and trigger `_onDidChangeBackgroundTasks`. The `PanelViewProvider` monitors and displays these running background tasks.
 
 ## Run Settings
 
-- **`runSettingsCommands.ts`**: Registers commands (`editRunSettings`, `resetRunSettings`) and provides default `languageTemplates`.
+- **`runSettingsCommands.ts`**: Registers commands (`editRunSettings`, `resetRunSettings`) and provides default `languageTemplates` for various languages (C++/GCC, C++/Clang, Python, PyPy, Java, Go, Rust, JavaScript, etc.).
 - **`vscode.ts`**: Provides `getFileRunSettings`, `initializeRunSettingsWatcher`, and `resolveVariables` to parse and resolve VS Code variables (like `${fileDirname}`) in commands.
 
+### Hierarchical Run Settings Merging
+
+`getFileRunSettings(file)` traverses from the file's directory up to the workspace root, loading and merging `runSettings.json` files along the way via `deepMerge()`. Closer-to-file settings override ancestor settings. The function also:
+
+- Applies defaults from the `runSettings.schema.json` schema file
+- Resolves VS Code variables via `resolveVariables()`
+- Validates via `RunSettingsSchema` (Valibot)
+- Caches loaded settings per directory; cache is invalidated by a `FileSystemWatcher`
+- Returns `FileRunSettings` which includes the merged settings plus the resolved `languageSettings` for the file's extension
+
 ## Extended VS Code Utilities (`vscode.ts`)
 
 - **`TextHandler`**: For all streamed output. Keeps full data internally, truncates display output, normalizes CRLF to LF, ensures trailing newline. Write modes: `"batch"`, `"force"`, `"final"`. Always call `.reset()` before a fresh run.
 - **`ReadonlyStringProvider`**: Manages the custom `fastolympiccoding` URI scheme for displaying read-only text documents.
 - **`openInNewEditor` / `openInTerminalTab`**: Helpers for displaying output. Terminal tabs support ANSI colors and native clickable file links.
 - **`openOrCreateFile`**: Helper for file management.
+- **`getFileWorkspace`**: Returns workspace folder or file directory. Used for run settings and CC target resolution.
+- **`getAttachDebugConfiguration`**: Looks up a named debug configuration from workspace `launch.json`.
+- **`showOpenRunSettingsErrorWindow` / `showAddLanguageSettingsError`**: Error UI helpers that offer quick-fix actions.
 
 ## UI/UX Features
 
@@ -59,6 +81,16 @@ Termination mapping helpers:
 
 Use `compile()` for compilation (caches by file checksum and compile command).
 
+### Debounced Saving
+
+JudgeViewProvider uses a debounced save pattern:
+
+- `requestSave()`: Schedules a bulk save after 200ms (resets timer on repeated calls)
+- `forceSave()`: Immediately saves all state (used during `onDispose()`)
+- `_saveAllState()`: Writes all contexts to workspaceState in a single bulk update
+
+StressViewProvider saves state synchronously via `_saveState(file)` after each operation.
+
 ## Debug Workflow
 
 Debug support uses **attach mode**:

.github/instructions/judge-provider.instructions.md

@@ -68,6 +68,8 @@ The `handleMessage` method dispatches based on `msg.type`. Top-level message typ
 - `NEW_INTERACTOR_SECRET`: Generates a new interactor secret
 - `ACTION`: Calls `this._action(msg)` which dispatches based on the `action` field
 
+- `REORDER`: Reorders a testcase to a new index position
+
 Actions handled by `_action`:
 
 - `RUN`: Execute single testcase
@@ -79,9 +81,10 @@ Actions handled by `_action`:
 - `TOGGLE_SKIP`: Toggle skip flag
 - `COMPARE`: Open diff view
 - `DEBUG`: Run in debug mode
-- `OPEN_INTERACTOR`: Open interactor file
 - `TOGGLE_INTERACTIVE`: Toggle interactive mode
 
+> Note: `REQUEST_DATA` exists in `ActionValues` but is not handled in `_action`.
+
 ## Background Task Tracking
 
 `_contexts` map holds contexts for all files (not just active). Methods:
@@ -101,3 +104,17 @@ Actions handled by `_action`:
 - `addTestcaseToFile(file, testcase, timeLimit?, memoryLimit?)`: Adds testcase from external source (Competitive Companion)
 - `exportTestcasesForFile(file)`: Serializes and exports testcases for a given file
 - `appendImportedTestcasesForFile(file, rawData)`: Parses, imports, and appends testcases to a file
+
+## Public API Methods
+
+- `getActiveFilePath()`: Returns the currently active file path
+- `runAll()` / `debugAll()` / `stopAll()`: Batch operations on all testcases for the current file
+- `deleteAll(file?)`: Delete all testcases for a file (defaults to current file)
+- `toggleWebviewSettings()`: Sends `SETTINGS_TOGGLE` to toggle the webview settings panel
+- `openInteractorFile()`: Opens the interactor file from run settings (separate from action dispatch)
+
+## Debounced Save Pattern
+
+- `requestSave()`: Schedules a bulk save after 200ms (debounced)
+- `forceSave()`: Immediately saves all state, used during `onDispose()`
+- `_saveAllState()`: Writes all contexts to workspaceState in a single bulk update

.github/instructions/shared-contracts.instructions.md

@@ -114,6 +114,17 @@ Derive property types from schemas using TypeScript utility types. For example:
 export type TestcaseProperty = Exclude<keyof Testcase, "uuid">;
 ```
 
+## Data Schemas (`schemas.ts`)
+
+Key schemas for persisted and exchanged data:
+
+- **`TestcaseSchema`**: Judge testcase with `uuid`, stdio fields, `elapsed`, `memoryBytes`, `status`, `shown`, `toggled`, `skipped`, `mode`, `interactorSecret`. Uses `v.fallback()` for all fields.
+- **`StressDataSchema`**: Stress state snapshot with `stdin`, `stdout`, `stderr`, `status`, `state` (StateId), `shown`.
+- **`RunSettingsSchema`**: Validated via `v.pipe()` with `v.looseObject()` and `v.check()`. Known keys: `interactorFile`, `goodSolutionFile`, `generatorFile`. Additional properties must be file extensions (starting with `.`) and match `LanguageSettingsSchema`.
+- **`LanguageSettingsSchema`**: Per-language config with optional `compileCommand`, `runCommand`, `currentWorkingDirectory`, `debugCommand`, `debugAttachConfig`.
+- **`ProblemSchema`**: Competitive Companion problem data with `name`, `group`, `url`, `tests`, `timeLimit`, `memoryLimit`, `interactive`, `batch`, `input`, `output`.
+- **`TestSchema`**: Simple `{ input, output }` for CC test pairs.
+
 ## Append-Only Rule
 
 When adding new enum values or message types, **append to the end** of arrays. Never rename or reorder existing values—they may be persisted in workspaceState.

.github/instructions/stress-provider.instructions.md

@@ -71,7 +71,8 @@ In interactive mode:
 - Generator produces a "secret" (like interactor in Judge)
 - The **Judge** acts as the interactor (running `interactorFile`), communicating back and forth with the **Solution** (the user's solution).
 - The **Generator** provides the initial secret to the Judge.
-- Uses `interactiveSecretPromise` to wait for webview to receive the secret
+- The secret is resolved immediately when the Generator emits stdout data (not when the webview receives it)
+- Uses `interactiveSecretPromise` to ensure the secret is sent before Solution stdout is forwarded to Judge
 
 ## State Persistence
 
@@ -100,9 +101,16 @@ The stdio content, status, state, and visibility are all persisted for each comp
 
 - `getRunningStressSessions()`: Returns array of file paths with running stress
 - `stopStressSession(file)`: Stop stress for a specific file
-- `stopAll()`: Stops all stress sessions across all files in the workspace
+- `stopAll()`: Stops all stress sessions across all files
 - `onDidChangeBackgroundTasks`: Event for PanelViewProvider
 
+## Public API Methods
+
+- `run()`: Public entry point, calls `_doRun`
+- `stop()`: Set stopFlag for the current file
+- `clear()`: Stop and clear all state, or set `clearFlag` if running
+- `toggleWebviewSettings()`: Sends `SETTINGS_TOGGLE` to toggle the webview settings panel
+
 ## Key Methods
 
 - `_createContext(file, persistedState)`: Initialize context with states

.github/instructions/webview-frontend.instructions.md

@@ -23,15 +23,15 @@ Receive messages in `App.svelte` via `window.addEventListener("message", ...)` i
 
 ### Judge View (`src/webview/judge/`)
 
-- **App.svelte**: Entry point, message handling, testcase list rendering
-- **TestcaseToolbar.svelte**: Status badges, action buttons (run, stop, debug, delete)
-- **Testcase.svelte**: Stdio textareas (stdin, stdout, stderr, acceptedStdout, interactorSecret)
+- **App.svelte**: Entry point, message handling, testcase list rendering, drag-and-drop reorder
+- **TestcaseToolbar.svelte**: Status badges, action buttons (run, stop, debug, delete, skip, drag handle)
+- **Testcase.svelte**: Stdio textareas (stdin, stdout, stderr, acceptedStdout, interactorSecret). Exports a `reset()` function called before re-running a testcase.
 
 Rendering pattern:
 
 ```svelte
 {#each testcases as testcase, index (testcase.uuid)}
-  <div class="testcase-item">
+  <div class="testcase-item" data-uuid={testcase.uuid}>
     <TestcaseToolbar {testcase} onprerun={() => handlePrerun(testcase.uuid)} />
     {#if testcase.status === "COMPILING" || testcase.skipped}
       <div class="half-opacity">
@@ -44,6 +44,15 @@ Rendering pattern:
 {/each}
 ```
 
+### Drag-and-Drop Reorder (Judge)
+
+Testcases support reordering via drag-and-drop and keyboard (Alt+Arrow). The flow:
+
+1. `handleDragStart`: Sets `draggingUuid` and `dataTransfer`
+2. `handleDragOver`: Calculates drop position (before/after) relative to hovered testcase, updates `separatorIndex`
+3. `handleDrop`: Calls `reorderTestcasesLocally()` for immediate UI update, then sends `REORDER` message to extension
+4. Keyboard: Alt+ArrowUp/Down in `handleTestcaseKeydown` calls `commitReorder()` directly
+
 ### Stress View (`src/webview/stress/`)
 
 - **App.svelte**: Entry point, message handling, state list rendering