feat(remaining): deferred tasks — error pages, UX, telemetry, domain

.gitignore

@@ -47,6 +47,10 @@ next-env.d.ts
 data/
 logs/*
 
+# analysis directories (generated, not tracked)
+.analysis/
+antigravity-manager-analysis/
+
 # docs (allow specific tracked files)
 docs/*
 !docs/ARCHITECTURE.md
@@ -56,6 +60,9 @@ docs/*
 !docs/TASK_NEBIUS_BACKEND_ENABLEMENT.md
 !docs/frontend-backend-provider-gap-report.md
 !docs/openapi.yaml
+!docs/PLANO-IMPLANTACAO.md
+!docs/TASKS.md
+!docs/FASE-*.md
 !docs/adr/
 !docs/cli-tools/
 !docs/planning/

src/app/global-error.js

@@ -0,0 +1,97 @@
+"use client";
+
+/**
+ * Global Error Page — FASE-04 Error Handling
+ *
+ * Root-level error boundary for unrecoverable errors.
+ * This is the last resort — catches errors that the per-page
+ * error.js boundaries don't handle.
+ */
+
+export default function GlobalError({ error, reset }) {
+  return (
+    <html>
+      <body
+        style={{
+          display: "flex",
+          flexDirection: "column",
+          alignItems: "center",
+          justifyContent: "center",
+          minHeight: "100vh",
+          padding: "24px",
+          background: "#0a0a0f",
+          color: "#e0e0e0",
+          fontFamily: "system-ui, -apple-system, sans-serif",
+          textAlign: "center",
+          margin: 0,
+        }}
+      >
+        <div
+          style={{
+            fontSize: "64px",
+            marginBottom: "16px",
+          }}
+        >
+          ⚠️
+        </div>
+        <h1
+          style={{
+            fontSize: "28px",
+            fontWeight: 700,
+            marginBottom: "8px",
+          }}
+        >
+          Something went wrong
+        </h1>
+        <p
+          style={{
+            fontSize: "15px",
+            color: "#888",
+            maxWidth: "400px",
+            lineHeight: 1.5,
+            marginBottom: "24px",
+          }}
+        >
+          An unexpected error occurred. This has been logged and our team will investigate.
+        </p>
+        {process.env.NODE_ENV === "development" && error?.message && (
+          <pre
+            style={{
+              padding: "16px",
+              borderRadius: "8px",
+              background: "rgba(239, 68, 68, 0.1)",
+              border: "1px solid rgba(239, 68, 68, 0.3)",
+              color: "#ef4444",
+              fontSize: "12px",
+              maxWidth: "600px",
+              overflow: "auto",
+              textAlign: "left",
+              marginBottom: "24px",
+            }}
+          >
+            {error.message}
+          </pre>
+        )}
+        <button
+          onClick={reset}
+          style={{
+            padding: "12px 32px",
+            borderRadius: "10px",
+            background: "linear-gradient(135deg, #6366f1, #8b5cf6)",
+            color: "#fff",
+            border: "none",
+            fontSize: "14px",
+            fontWeight: 600,
+            cursor: "pointer",
+            transition: "transform 0.2s",
+            boxShadow: "0 4px 16px rgba(99, 102, 241, 0.3)",
+          }}
+          onMouseEnter={(e) => (e.target.style.transform = "translateY(-2px)")}
+          onMouseLeave={(e) => (e.target.style.transform = "translateY(0)")}
+        >
+          Try Again
+        </button>
+      </body>
+    </html>
+  );
+}

src/app/not-found.js

@@ -0,0 +1,77 @@
+"use client";
+
+/**
+ * Custom Not Found Page — FASE-04 Error Handling
+ *
+ * Displayed when a user navigates to a non-existent route.
+ */
+
+import Link from "next/link";
+
+export default function NotFound() {
+  return (
+    <div
+      style={{
+        display: "flex",
+        flexDirection: "column",
+        alignItems: "center",
+        justifyContent: "center",
+        minHeight: "100vh",
+        padding: "24px",
+        background: "var(--bg-primary, #0a0a0f)",
+        color: "var(--text-primary, #e0e0e0)",
+        textAlign: "center",
+      }}
+    >
+      <div
+        style={{
+          fontSize: "96px",
+          fontWeight: 800,
+          background: "linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%)",
+          WebkitBackgroundClip: "text",
+          WebkitTextFillColor: "transparent",
+          lineHeight: 1,
+          marginBottom: "8px",
+        }}
+      >
+        404
+      </div>
+      <h1
+        style={{
+          fontSize: "24px",
+          fontWeight: 600,
+          marginBottom: "8px",
+        }}
+      >
+        Page not found
+      </h1>
+      <p
+        style={{
+          fontSize: "15px",
+          color: "var(--text-secondary, #888)",
+          maxWidth: "400px",
+          lineHeight: 1.5,
+          marginBottom: "32px",
+        }}
+      >
+        The page you&apos;re looking for doesn&apos;t exist or has been moved.
+      </p>
+      <Link
+        href="/dashboard"
+        style={{
+          padding: "12px 32px",
+          borderRadius: "10px",
+          background: "linear-gradient(135deg, #6366f1, #8b5cf6)",
+          color: "#fff",
+          fontSize: "14px",
+          fontWeight: 600,
+          textDecoration: "none",
+          transition: "all 0.2s",
+          boxShadow: "0 4px 16px rgba(99, 102, 241, 0.3)",
+        }}
+      >
+        Go to Dashboard
+      </Link>
+    </div>
+  );
+}

src/domain/comboResolver.js

@@ -0,0 +1,93 @@
+/**
+ * Combo Resolver — FASE-09 Domain Extraction (T-46)
+ *
+ * Extracts combo resolution logic from handleChat into a dedicated
+ * domain service. Handles model selection based on combo strategy
+ * (priority, round-robin, random, least-used).
+ *
+ * @module domain/comboResolver
+ */
+
+/**
+ * @typedef {import('./types.js').Combo} Combo
+ */
+
+/**
+ * Resolve which model to use from a combo based on its strategy.
+ *
+ * @param {Combo} combo - The combo configuration
+ * @param {{ modelUsageCounts?: Record<string, number> }} [context] - Optional context
+ * @returns {{ model: string, index: number }}
+ * @throws {Error} If combo has no models
+ */
+export function resolveComboModel(combo, context = {}) {
+  const models = combo.models || [];
+  if (models.length === 0) {
+    throw new Error(`Combo "${combo.name}" has no models configured`);
+  }
+
+  // Normalize models to { model, weight } format
+  const normalized = models.map((m) =>
+    typeof m === "string" ? { model: m, weight: 1 } : m
+  );
+
+  const strategy = combo.strategy || "priority";
+
+  switch (strategy) {
+    case "priority":
+      return { model: normalized[0].model, index: 0 };
+
+    case "round-robin": {
+      // Use a simple counter based on current time + combo id hash
+      const tick = Date.now() % normalized.length;
+      return { model: normalized[tick].model, index: tick };
+    }
+
+    case "random": {
+      // Weighted random selection
+      const totalWeight = normalized.reduce((sum, m) => sum + (m.weight || 1), 0);
+      let rand = Math.random() * totalWeight;
+
+      for (let i = 0; i < normalized.length; i++) {
+        rand -= normalized[i].weight || 1;
+        if (rand <= 0) {
+          return { model: normalized[i].model, index: i };
+        }
+      }
+      return { model: normalized[0].model, index: 0 };
+    }
+
+    case "least-used": {
+      const usageCounts = context.modelUsageCounts || {};
+      let minUsage = Infinity;
+      let minIndex = 0;
+
+      for (let i = 0; i < normalized.length; i++) {
+        const usage = usageCounts[normalized[i].model] || 0;
+        if (usage < minUsage) {
+          minUsage = usage;
+          minIndex = i;
+        }
+      }
+
+      return { model: normalized[minIndex].model, index: minIndex };
+    }
+
+    default:
+      return { model: normalized[0].model, index: 0 };
+  }
+}
+
+/**
+ * Get the fallback models for a combo (all models except the primary).
+ *
+ * @param {Combo} combo
+ * @param {number} primaryIndex - Index of the primary model
+ * @returns {string[]} Remaining models in order
+ */
+export function getComboFallbacks(combo, primaryIndex) {
+  const models = (combo.models || []).map((m) =>
+    typeof m === "string" ? m : m.model
+  );
+  return [...models.slice(primaryIndex + 1), ...models.slice(0, primaryIndex)];
+}