Stand-in import of elffuss/code

One parentless commit with only the files that the open seed tasks touch and the modules they import.
The full squashed import (SPEC 8.6) is a later step: this tree is not the cutoff tree.

T2T-StandIn-Source-Commit: 43f95b7333efe73aeaebf806023f17bffea27aba

web/js/providers/api.js

@@ -0,0 +1,122 @@
+// Proveedor genérico para APIs externas (configuración avanzada):
+//  - kind 'openai'    → /chat/completions (OpenAI, Ollama, llama-server…)
+//  - kind 'anthropic' → /v1/messages (Claude)
+// Las llamadas salen DIRECTAS del navegador del usuario al proveedor; la clave
+// no pasa por ningún servidor nuestro. Streaming SSE en ambos dialectos.
+import { packHistoryAsync } from '../context.js';
+
+let cfg = null;
+export let name = 'API';
+
+export function configure(c) { cfg = c; name = c.label; }
+
+export async function load() {
+  if (!cfg) throw new Error('proveedor sin configurar');
+  if (cfg.kind !== 'anthropic' && !cfg.apiKey && !cfg.baseURL.includes('localhost') && cfg.baseURL !== '/v1')
+    throw new Error('falta la clave de API (config avanzada)');
+}
+
+export async function chat(history, system, onToken = () => {}, signal = null) {
+  return cfg.kind === 'anthropic'
+    ? anthropicChat(history, system, onToken)
+    : openaiChat(history, system, onToken);
+}
+
+// ---- OpenAI-compatible ----
+async function openaiChat(history, system, onToken) {
+  const headers = { 'Content-Type': 'application/json' };
+  if (cfg.apiKey) headers.Authorization = 'Bearer ' + cfg.apiKey;
+  // packHistoryAsync: el empaquetado puede tener que codificar embeddings, así
+  // que se resuelve ANTES de armar el cuerpo. Con el lado semántico apagado
+  // devuelve exactamente lo mismo que la versión síncrona de siempre.
+  const packed = await packHistoryAsync(history, 3000);
+  const body = {
+    model: cfg.model,
+    messages: [{ role: 'system', content: system }, ...packed],
+    stream: true,
+    max_tokens: cfg.maxTokens || 1024,
+  };
+  if (cfg.temperature != null) body.temperature = cfg.temperature;
+  if (cfg.top_p != null) body.top_p = cfg.top_p;
+  if (cfg.thinking != null) body.chat_template_kwargs = { enable_thinking: cfg.thinking };
+
+  const res = await fetch(cfg.baseURL.replace(/\/$/, '') + '/chat/completions', {
+    signal,
+    method: 'POST', headers, body: JSON.stringify(body),
+  });
+  if (!res.ok || !res.body) throw new Error('HTTP ' + res.status + ' ' + (await res.text().catch(() => '')).slice(0, 120));
+
+  let out = '';
+  await readSSE(res.body, payload => {
+    if (payload === '[DONE]') return;
+    const d = JSON.parse(payload).choices?.[0]?.delta || {};
+    if (d.reasoning_content) onToken(d.reasoning_content);
+    if (d.content) { out += d.content; onToken(d.content); }
+  });
+  return out.trim();
+}
+
+// ---- Anthropic Messages ----
+async function anthropicChat(history, system, onToken) {
+  const packed = await packHistoryAsync(history, 3000);
+  const res = await fetch(cfg.baseURL.replace(/\/$/, '') + '/v1/messages', {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/json',
+      'x-api-key': cfg.apiKey,
+      'anthropic-version': '2023-06-01',
+      'anthropic-dangerous-direct-browser-access': 'true',
+    },
+    body: JSON.stringify({
+      model: cfg.model,
+      max_tokens: cfg.maxTokens || 1024,
+      system,
+      stream: true,
+      messages: forAnthropic(packed),
+    }),
+  });
+  if (!res.ok || !res.body) throw new Error('HTTP ' + res.status + ' ' + (await res.text().catch(() => '')).slice(0, 120));
+
+  let out = '';
+  await readSSE(res.body, payload => {
+    const evt = JSON.parse(payload);
+    if (evt.type === 'content_block_delta' && evt.delta?.text) {
+      out += evt.delta.text; onToken(evt.delta.text);
+    }
+  });
+  return out.trim();
+}
+
+// Anthropic exige roles alternos empezando por user; fusiona consecutivos.
+function forAnthropic(msgs) {
+  const merged = [];
+  for (const m of msgs) {
+    const role = m.role === 'assistant' ? 'assistant' : 'user';
+    const last = merged[merged.length - 1];
+    if (last && last.role === role) last.content += '\n' + m.content;
+    else merged.push({ role, content: m.content });
+  }
+  if (merged[0]?.role === 'assistant') merged.unshift({ role: 'user', content: '(continúa)' });
+  return merged;
+}
+
+// Lector SSE común: invoca fn con el texto tras cada 'data:'.
+async function readSSE(stream, fn) {
+  const reader = stream.getReader();
+  const dec = new TextDecoder();
+  let buf = '';
+  for (;;) {
+    const { done, value } = await reader.read();
+    if (done) break;
+    buf += dec.decode(value, { stream: true });
+    let nl;
+    while ((nl = buf.indexOf('\n')) >= 0) {
+      const line = buf.slice(0, nl).trim();
+      buf = buf.slice(nl + 1);
+      if (!line.startsWith('data:')) continue;
+      const payload = line.slice(5).trim();
+      if (!payload) continue;
+      try { fn(payload); } catch { /* chunk parcial */ }
+    }
+  }
+}