feat(contest): add ICPC Prelim contest table provider

.claude/rules/svelte-components.md

@@ -83,6 +83,25 @@ Import from `flowbite-svelte`. Use Tailwind v4 `dark:` prefix. When copying butt
 - Move business logic to `_utils/` or `utils/` with tests
 - Keep components thin: one responsibility
 
+## `{@const}` Placement Restriction
+
+`{@const}` is only valid as the immediate child of a control-flow block (`{#if}`, `{#each}`, `{:else}`, etc.) — placing it at the template top level is a compile error.
+
+When you need a derived value in both a `{#if}` condition and its body, declare it with `$derived` in `<script>` instead:
+
+```typescript
+// ✅ in <script>
+let groupMetadata = $derived(store?.getMetadata());
+```
+
+```svelte
+{#if groupMetadata?.mainTitle}
+  <Heading>{groupMetadata.mainTitle}</Heading>
+{/if}
+```
+
+This also avoids calling the getter twice per render.
+
 ## Reactive Data Pitfalls
 
 - `let` captures initial value only; use `$derived` for derived/prop data

.claude/rules/testing.md

@@ -112,6 +112,25 @@ afterEach(() => {
 });
 ```
 
+### Mutable Module-Level Exports
+
+When a module exports a mutable `const` object (e.g. an override map), mutate it directly in `beforeEach`/`afterEach` to test override paths — no `vi.mock` needed:
+
+```typescript
+import { buildFn, OVERRIDE_MAP } from './module';
+
+beforeEach(() => {
+  OVERRIDE_MAP['testKey'] = { '100': 'A', '102': 'C' };
+});
+afterEach(() => {
+  delete OVERRIDE_MAP['testKey'];
+});
+
+test('uses override map when entry exists', () => {
+  expect(buildFn('testKey', ['100', '102']).get('100')).toBe('A');
+});
+```
+
 ### Test Stubs
 
 Parameter types **must match** production signature — use domain types (`TaskGrade`), not `string`. Mismatch compiles silently but breaks type safety.

.claude/skills/add-contest-table-provider/instructions.md

@@ -14,6 +14,7 @@ Step 0 (seed check) is already done. Confirm the following before touching code:
   - Pattern 1: numeric range filter (e.g. ABC 001–041)
   - Pattern 2: single fixed contest_id (e.g. NDPC, TDPC, FPS_24)
   - Pattern 3: multiple contest_ids unified in one table (e.g. ABS, ABC-Like)
+  - Pattern 4: one class instantiated N times via constructor parameter (e.g. ICPC Prelim by year)
 - Nearest neighbor ContestType for insertion order in `contestTypePriorities`?
 - New group or merge into existing? If new: group name / `buttonLabel` / `ariaLabel`?
 
@@ -23,6 +24,15 @@ Step 0 (seed check) is already done. Confirm the following before touching code:
 - Shared problems with another contest (e.g. ARC–ABC overlap)? Which contest_ids appear in both?
 - Round label format (e.g. `ABC 042`)?
 
+**Pattern 4 additional:**
+
+- Constructor parameter name and type (e.g. `year: number`)?
+- Year/ID range: oldest and latest? Export both as named constants so tests can reference them.
+- Iteration order: latest-first so newest table renders on top.
+- `task_table_index` values numeric strings? → override `getHeaderIdsForTask`; sort with `Number(a) - Number(b)`.
+- Display-only title transform needed (e.g. prepend letter)? → override `generateTable` for the transform AND override `getHeaderIdsForTask` using the same key derivation; mismatched keys between the two methods cause missing cells.
+- Known edge cases where the default algorithm breaks? → add a `Record<string, Record<string, string>>` module-level override map keyed by contest_id; exercise the override path in tests by mutating the export in `beforeEach` and cleaning up in `afterEach`.
+
 **Pattern 3 additional:**
 
 - Show the full contest_id list found in `prisma/tasks.ts` — any missing or to exclude?
@@ -87,6 +97,16 @@ Step 0 (seed check) is already done. Confirm the following before touching code:
 - [ ] Implement Provider using `parseContestRound()` range check
 - [ ] `pnpm test:unit <providers.test.ts>` — **expect GREEN**
 
+### Pattern 4: N-instances via constructor parameter
+
+- [ ] Export `OLDEST_YEAR` / `LATEST_YEAR` constants (module-level, before `prepareContestProviderPresets`) so tests can assert `getSize() === LATEST - OLDEST + 1`
+- [ ] Pass the parameter as `section` in `super(contestType, String(param))` → provider key becomes `TYPE::value` (unique per instance)
+- [ ] If `generateTable` is overridden to key the table by `task_table_index` directly: also override `getHeaderIdsForTask` using the same field and sort order
+- [ ] If display title needs transformation (e.g. prepend "A. "): do it inside `generateTable`; DB data must remain unchanged
+- [ ] Write override map (`Record<string, Record<string, value>>`) for known edge cases; test the override path by mutating the export in `beforeEach` and cleaning up in `afterEach`
+- [ ] If provider headings need non-default font/weight/gap: return `titleStyle` (`headingTag` / `fontSize` / `fontWeight` / `bottomGap`) from `getMetadata()`; include all set fields in the `titleStyle` assertion
+- [ ] `pnpm test:unit <providers.test.ts>` — **expect GREEN**
+
 ### Pattern 3: composite
 
 - [ ] Confirm whether `prisma/contest_task_pairs.ts` needs new entries before writing tests
@@ -101,14 +121,15 @@ Step 0 (seed check) is already done. Confirm the following before touching code:
 ## Layer 5 — Group registration (TDD)
 
 - [ ] Update `contest_table_provider_groups.test.ts`:
-  - New group name string, `buttonLabel`, `ariaLabel`
+  - New group name string, `buttonLabel`, `ariaLabel` (add `mainTitle` if used)
   - `getSize()` incremented to reflect the new provider count
   - Add `getProvider(ContestType.XXX)` assertion
   - Add import of new Provider class
 - [ ] `pnpm test:unit contest_table_provider_groups.test.ts` — **expect RED**
 - [ ] Update `contest_table_provider_groups.ts`:
   - Add import of new Provider class
   - Update group name string, `buttonLabel`, `ariaLabel`
+  - Add `mainTitle: 'XXX'` if the group needs a single h2 heading rendered above all providers (opt-in; omit when not needed)
   - Add `new XXXProvider(ContestType.XXX)` to `addProviders()`
 - [ ] `pnpm test:unit src/features/tasks/utils/contest-table/` — **expect GREEN**
 

docs/guides/how-to-add-contest-table-provider.md

@@ -33,6 +33,7 @@
   - **パターン1（範囲フィルタ型）**: ABC 001～041、ARC 058～103 など → 数値範囲でフィルタ
   - **パターン2（単一ソース型）**: EDPC、TDPC、ACL_PRACTICE など → 単一 contest_id のみ
   - **パターン3（複合ソース型）**: ABS、ABC-Like など → 複数 contest_id を統一表示
+  - **パターン4（コンストラクタパラメータ型）**: ICPC 国内予選など → 1クラスをコンストラクタ引数（年度等）で N 回インスタンス化
   - 対応セクション: [実装パターン](#実装パターン)
 
 - [ ] **JOI の contest_id サフィックス変更の確認**
@@ -192,6 +193,66 @@ protected setFilterCondition(): (taskResult: TaskResult) => boolean {
 
 ---
 
+### パターン4: コンストラクタパラメータ型（ICPC 国内予選）
+
+**特徴**:
+
+- 年度などのパラメータを受け取る1つのクラスを N 回インスタンス化
+- `super(contestType, String(year))` でセクションを年度文字列にし、プロバイダキーを `AOJ_ICPC::2025` のように一意化
+- 年度範囲定数（`OLDEST_YEAR` / `LATEST_YEAR`）をモジュールトップで `export` し、tests でも参照できるようにする
+- グループ登録時は最新年から古い年へ降順ループし、テーブルを新しい順に並べる
+
+**実装例**:
+
+```typescript
+export const ICPC_PRELIM_OLDEST_YEAR = 1998;
+export const ICPC_PRELIM_LATEST_YEAR = 2025;
+
+export class AojIcpcPrelimProvider extends ContestTableProviderBase {
+  private readonly year: number;
+  private readonly contestId: string;
+
+  constructor(contestType: ContestType, year: number) {
+    super(contestType, String(year)); // provider key: AOJ_ICPC::2025
+    this.year = year;
+    this.contestId = `ICPCPrelim${year}`;
+  }
+  // ...
+}
+
+// グループ登録（最新年が上に来るよう降順）
+for (let year = ICPC_PRELIM_LATEST_YEAR; year >= ICPC_PRELIM_OLDEST_YEAR; year--) {
+  group.addProvider(new AojIcpcPrelimProvider(ContestType.AOJ_ICPC, year));
+}
+```
+
+**注意**:
+
+- `generateTable` をオーバーライドして `task_table_index` をキーにする場合、`getHeaderIdsForTask` も**必ず同じフィールド・同じソート順**でオーバーライドすること。ベースクラスの `getHeaderIdsForTask` は `getTaskTableHeaderName()` 経由でキーを導出するため、`generateTable` と一致しないとセルが表示されない。
+- `task_table_index` が数値文字列（例: `'1664'`）の場合、辞書順ではなく数値昇順ソートが必要: `Number(a) - Number(b)`
+- アルゴリズムが成立しない例外年度には上書き Map を用意する:
+
+```typescript
+// contest_id -> (task_table_index -> letter). Used only for years with judge gaps.
+export const ICPC_PRELIM_LABEL_OVERRIDES: Record<string, Record<string, string>> = {};
+```
+
+上書き Map のテストは `beforeEach`/`afterEach` でエントリを直接追加・削除する（`vi.mock` 不要）:
+
+```typescript
+beforeEach(() => {
+  ICPC_PRELIM_LABEL_OVERRIDES['ICPCPrelimTest'] = { '1150': 'A', '1152': 'C' };
+});
+afterEach(() => {
+  delete ICPC_PRELIM_LABEL_OVERRIDES['ICPCPrelimTest'];
+});
+```
+
+- グループ全体に一度だけ大見出し（h2）を表示したい場合は、グループ登録時に `mainTitle: 'XXX'` を追加する。省略すると描画されない。個々の provider の `title` が冗長になるなら年や回だけに絞っても良い（ICPC 国内予選は敢えて重複させた）。
+- provider 見出しのフォント・太字・余白をデフォルトから変えたい場合は `getMetadata()` で `titleStyle` を返す。`ContestTableTitleStyle`（`headingTag` / `fontSize` / `fontWeight` / `bottomGap`）のうち必要なフィールドだけ指定すればよい。
+
+---
+
 ### パターン3: 複合ソース型（ABS / TESSOKU_BOOK / MATH_AND_ALGORITHM）
 
 **特徴**: