feat(arr): render subtitle settings in /settings

Adds wanted languages, translation engine (restricted to
available_engines), remote-command timeout, and an ordered
enable/disable list per provider with daily budgets, wired to
the existing GET/PUT /api/settings/subtitles from #198.

web/index.html

@@ -468,6 +468,17 @@
         </p>
         <ul class="deck-rows" id="rows-policies"></ul>
       </section>
+
+      <section class="deck-group" id="group-subtitles" hidden aria-labelledby="label-settings-subtitles">
+        <header class="deck-head">
+          <h3 class="deck-label" id="label-settings-subtitles">subtitles</h3>
+        </header>
+        <p class="queue-note readout dim">
+          provider credentials, translator keys and the remote-command template
+          live in config/env (§10) and are never shown here.
+        </p>
+        <div id="subtitles-body"></div>
+      </section>
     </main>
 
     <!--

web/src/settings.ts

@@ -35,6 +35,22 @@ export interface RootInput {
 
 const RESOLUTIONS = ["2160p", "1080p", "720p"] as const;
 const SOURCES = ["Remux", "BluRay", "WEB-DL", "WEBRip", "HDTV"] as const;
+/** DESIGN.md §15: OpenSubtitles and Podnapisi, no cargo feature gate. */
+const PROVIDERS = ["opensubtitles", "podnapisi"] as const;
+
+/** The runtime-editable half of subtitle config (§15) — issue #198's shape. */
+export interface SubtitleSettings {
+  wanted_languages: string[];
+  providers_enabled: string[];
+  translation_engine: string | null;
+  provider_daily_budgets: Record<string, number>;
+  translator_daily_budgets: Record<string, number>;
+  remote_command_timeout_seconds: number;
+  /** Engines this binary compiled in — `translation_engine` is always one of these, or null. */
+  available_engines: string[];
+}
+
+export type SubtitleSettingsInput = Omit<SubtitleSettings, "available_engines">;
 
 async function errorDetail(response: Response): Promise<string> {
   try {
@@ -61,6 +77,18 @@ async function fetchRoots(): Promise<Root[]> {
   return (await response.json()) as Root[];
 }
 
+async function fetchSubtitleSettings(): Promise<SubtitleSettings> {
+  const response = await fetch("/api/settings/subtitles");
+  if (!response.ok) {
+    throw new Error(await errorDetail(response));
+  }
+  return (await response.json()) as SubtitleSettings;
+}
+
+function saveSubtitleSettings(input: SubtitleSettingsInput): Promise<SaveOutcome> {
+  return sendJson("/api/settings/subtitles", "PUT", input);
+}
+
 type SaveOutcome = { ok: true; json: unknown } | { ok: false; detail: string };
 
 async function sendJson(url: string, method: string, body: unknown): Promise<SaveOutcome> {
@@ -237,9 +265,12 @@ export function settingsMain(views: { hide: () => void }[], goHome: () => void):
   const rootsRows = must<HTMLUListElement>("#rows-roots");
   const policiesSection = must<HTMLElement>("#group-policies");
   const policiesRows = must<HTMLUListElement>("#rows-policies");
+  const subtitlesSection = must<HTMLElement>("#group-subtitles");
+  const subtitlesBody = must<HTMLElement>("#subtitles-body");
 
   let roots: Root[] = [];
   let policies: PolicyDoc[] = [];
+  let subtitleSettings: SubtitleSettings | null = null;
   // guards a stale fetch from painting over a newer view
   let sequence = 0;
 
@@ -254,11 +285,12 @@ export function settingsMain(views: { hide: () => void }[], goHome: () => void):
   }
 
   function clearGroups() {
-    for (const section of [rootsSection, policiesSection]) {
+    for (const section of [rootsSection, policiesSection, subtitlesSection]) {
       section.hidden = true;
     }
     rootsRows.replaceChildren();
     policiesRows.replaceChildren();
+    subtitlesBody.replaceChildren();
     summary.textContent = "";
   }
 
@@ -267,12 +299,17 @@ export function settingsMain(views: { hide: () => void }[], goHome: () => void):
     const ticket = sequence;
     setStatus("reading settings…");
     try {
-      const [fetchedRoots, fetchedPolicies] = await Promise.all([fetchRoots(), fetchPolicies()]);
+      const [fetchedRoots, fetchedPolicies, fetchedSubtitleSettings] = await Promise.all([
+        fetchRoots(),
+        fetchPolicies(),
+        fetchSubtitleSettings(),
+      ]);
       if (ticket !== sequence) {
         return;
       }
       roots = fetchedRoots;
       policies = fetchedPolicies;
+      subtitleSettings = fetchedSubtitleSettings;
     } catch (error) {
       if (ticket !== sequence) {
         return;
@@ -296,6 +333,10 @@ export function settingsMain(views: { hide: () => void }[], goHome: () => void):
     for (const policy of policies) {
       policiesRows.append(policyRow(policy));
     }
+    if (subtitleSettings) {
+      subtitlesSection.hidden = false;
+      subtitlesBody.append(subtitlesPanel(subtitleSettings));
+    }
   }
 
   /* -- roots -------------------------------------------------------------- */
@@ -700,6 +741,193 @@ export function settingsMain(views: { hide: () => void }[], goHome: () => void):
     return panel;
   }
 
+  /* -- subtitles ------------------------------------------------------------ */
+
+  /**
+   * One row per known provider, checkbox to enable, a daily-budget number,
+   * and up/down controls — list order is the priority order the API stores
+   * in `providers_enabled`. Disabled providers stay in the list, at
+   * whatever position they were left, so re-enabling one keeps its spot.
+   */
+  function providerRow(
+    provider: string,
+    enabled: boolean,
+    budget: number,
+  ): { item: HTMLLIElement; enabledInput: HTMLInputElement; budgetInput: HTMLInputElement } {
+    const item = el("li", "provider-row");
+    item.dataset.provider = provider;
+
+    const enabledInput = document.createElement("input");
+    enabledInput.type = "checkbox";
+    enabledInput.className = "provider-toggle";
+    enabledInput.checked = enabled;
+    enabledInput.setAttribute("aria-label", `enable ${provider}`);
+
+    const name = el("span", "row-title provider-name", provider);
+
+    const budgetInput = numberControl(budget);
+    budgetInput.classList.add("provider-budget");
+    budgetInput.setAttribute("aria-label", `${provider} daily budget`);
+
+    const up = el("button", "control control-quiet readout provider-move", "up");
+    up.type = "button";
+    up.setAttribute("aria-label", `move ${provider} up`);
+    const down = el("button", "control control-quiet readout provider-move", "down");
+    down.type = "button";
+    down.setAttribute("aria-label", `move ${provider} down`);
+
+    up.addEventListener("click", () => {
+      const previous = item.previousElementSibling;
+      if (previous) {
+        previous.before(item);
+        refreshProviderEdges();
+      }
+    });
+    down.addEventListener("click", () => {
+      const next = item.nextElementSibling;
+      if (next) {
+        next.after(item);
+        refreshProviderEdges();
+      }
+    });
+
+    item.append(enabledInput, name, budgetInput, up, down);
+    return { item, enabledInput, budgetInput };
+  }
+
+  let refreshProviderEdges: () => void = () => {};
+
+  function subtitlesPanel(settings: SubtitleSettings): HTMLElement {
+    const panel = el("div", "add-panel subtitle-panel");
+    const grid = el("div", "form-grid");
+
+    const wanted = textControl(settings.wanted_languages.join(", "), "pt-PT, en");
+    grid.append(field("wanted languages", wanted));
+
+    const hasEngines = settings.available_engines.length > 0;
+    const engineSelect = selectControl(
+      ["none", ...settings.available_engines],
+      settings.translation_engine ?? "none",
+    );
+    engineSelect.disabled = !hasEngines;
+    grid.append(field("translation engine", engineSelect));
+
+    const timeout = numberControl(settings.remote_command_timeout_seconds);
+    grid.append(field("remote command timeout (s)", timeout));
+
+    panel.append(grid);
+    if (!hasEngines) {
+      panel.append(
+        el(
+          "p",
+          "add-note readout dim",
+          "no translation engine is compiled into this binary — pick is unavailable",
+        ),
+      );
+    }
+
+    const translatorInputs: Record<string, HTMLInputElement> = {};
+    if (hasEngines) {
+      panel.append(el("p", "field-label readout dim", "translator daily budgets"));
+      const translatorGrid = el("div", "form-grid");
+      for (const engine of settings.available_engines) {
+        const input = numberControl(settings.translator_daily_budgets[engine] ?? 0);
+        input.setAttribute("aria-label", `${engine} daily budget`);
+        translatorInputs[engine] = input;
+        translatorGrid.append(field(engine, input));
+      }
+      panel.append(translatorGrid);
+    }
+
+    panel.append(el("p", "field-label readout dim", "providers — enabled, and in priority order"));
+    const enabledProviders = new Set(settings.providers_enabled);
+    const order = [
+      ...settings.providers_enabled,
+      ...PROVIDERS.filter((provider) => !enabledProviders.has(provider)),
+    ];
+    const list = el("ul", "provider-list");
+    const rows: Record<string, { enabledInput: HTMLInputElement; budgetInput: HTMLInputElement }> =
+      {};
+    for (const provider of order) {
+      const { item, enabledInput, budgetInput } = providerRow(
+        provider,
+        enabledProviders.has(provider),
+        settings.provider_daily_budgets[provider] ?? 0,
+      );
+      rows[provider] = { enabledInput, budgetInput };
+      list.append(item);
+    }
+    refreshProviderEdges = () => {
+      const items = [...list.children];
+      items.forEach((item, index) => {
+        const up = item.querySelector<HTMLButtonElement>("button:nth-of-type(1)");
+        const down = item.querySelector<HTMLButtonElement>("button:nth-of-type(2)");
+        if (up) up.disabled = index === 0;
+        if (down) down.disabled = index === items.length - 1;
+      });
+    };
+    refreshProviderEdges();
+    panel.append(list);
+
+    const note = el("p", "add-note readout");
+    note.setAttribute("role", "status");
+    note.hidden = true;
+
+    const save = el("button", "control readout", "save subtitles");
+    save.type = "button";
+    save.addEventListener("click", () => {
+      const providerOrder = [...list.children].map(
+        (item) => (item as HTMLElement).dataset.provider ?? "",
+      );
+      const providersEnabled = providerOrder.filter(
+        (provider) => rows[provider]?.enabledInput.checked,
+      );
+      const providerBudgets: Record<string, number> = {};
+      for (const provider of providerOrder) {
+        const value = Number(rows[provider]?.budgetInput.value ?? 0);
+        if (value > 0) {
+          providerBudgets[provider] = value;
+        }
+      }
+      const translatorBudgets: Record<string, number> = {};
+      for (const [engine, input] of Object.entries(translatorInputs)) {
+        const value = Number(input.value);
+        if (value > 0) {
+          translatorBudgets[engine] = value;
+        }
+      }
+
+      save.disabled = true;
+      note.hidden = false;
+      delete note.dataset.tone;
+      note.textContent = "saving…";
+      const input: SubtitleSettingsInput = {
+        wanted_languages: listValue(wanted),
+        providers_enabled: providersEnabled,
+        translation_engine: engineSelect.value === "none" ? null : engineSelect.value,
+        provider_daily_budgets: providerBudgets,
+        translator_daily_budgets: translatorBudgets,
+        remote_command_timeout_seconds: Number(timeout.value),
+      };
+      void saveSubtitleSettings(input).then((outcome) => {
+        if (outcome.ok) {
+          void load();
+          return;
+        }
+        save.disabled = false;
+        note.hidden = false;
+        note.dataset.tone = "fault";
+        note.textContent = outcome.detail;
+      });
+    });
+
+    const actions = el("div", "add-actions");
+    actions.append(save, note);
+    panel.append(actions);
+
+    return panel;
+  }
+
   /* -- shell ---------------------------------------------------------------- */
 
   function open() {

web/src/style.css

@@ -2115,3 +2115,45 @@ select.form-input {
 .band-num {
   width: 4.5rem;
 }
+
+/* ---- subtitle settings (§15, issue #204) ------------------------------ */
+
+.subtitle-panel .field-label {
+  display: block;
+  margin: var(--space-4) 0 var(--space-2);
+}
+
+.provider-list {
+  margin: 0 0 var(--space-3);
+  padding: 0;
+  list-style: none;
+}
+
+.provider-row {
+  display: flex;
+  align-items: center;
+  gap: var(--space-2);
+  padding: var(--space-2) var(--space-1);
+  border-bottom: 1px solid oklch(from var(--line) l c h / 45%);
+}
+
+.provider-toggle {
+  accent-color: var(--accent);
+}
+
+.provider-name {
+  flex: 1;
+  min-width: 0;
+}
+
+.provider-budget {
+  width: 5.5rem;
+}
+
+.provider-move {
+  min-width: 3rem;
+}
+
+.provider-move:disabled {
+  visibility: hidden;
+}