feat: multi-provider AI assistant, repo URL simplification

- lib/ai.ts: unified AI client supporting Anthropic (native format) and
  OpenAI-compatible providers (OpenAI, Perplexity, Ollama, OpenRouter, custom)
- settings: 6-provider chip selector, base URL auto-filled on preset select,
  Anthropic URL hidden (fixed), model/key placeholders per provider
- settings: git repo config replaced by single Repo URL field (.git paste)
  auto-parsed to instance URL + owner + repo at save time
- new.tsx: Suggest button between Symptom and Root Cause, visible when AI
  enabled and title+symptom filled; pre-fills rootCause and fix inline

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/new.tsx

@@ -19,6 +19,7 @@ import {
 } from "@/lib/db";
 import { Colors } from "@/constants/theme";
 import { useVoice } from "@/hooks/useVoice";
+import { callAI } from "@/lib/ai";
 import type { IncidentDraft } from "@/types/incident";
 
 const FIELD_STYLE = {
@@ -72,6 +73,9 @@ export default function NewIncidentScreen() {
   });
   const [tagInput, setTagInput] = useState("");
   const [saving, setSaving] = useState(false);
+  const [suggesting, setSuggesting] = useState(false);
+  const [suggestError, setSuggestError] = useState("");
+  const [aiEnabled, setAiEnabled] = useState(false);
   const [knownServices, setKnownServices] = useState<string[]>([]);
   const [serviceFocused, setServiceFocused] = useState(false);
 
@@ -81,6 +85,7 @@ export default function NewIncidentScreen() {
 
   useEffect(() => {
     getDistinctServices().then(setKnownServices);
+    SecureStore.getItemAsync("pref_ai_enabled").then((v) => setAiEnabled(v === "true"));
   }, []);
 
   useEffect(() => {
@@ -149,6 +154,19 @@ export default function NewIncidentScreen() {
     setForm((f) => ({ ...f, tags: f.tags.filter((t) => t !== tag) }));
   }
 
+  async function handleSuggest() {
+    setSuggesting(true);
+    setSuggestError("");
+    try {
+      const result = await callAI(form.title, form.symptom);
+      setForm((f) => ({ ...f, rootCause: result.rootCause, fix: result.fix }));
+    } catch (e) {
+      setSuggestError(e instanceof Error ? e.message : "AI call failed");
+    } finally {
+      setSuggesting(false);
+    }
+  }
+
   async function handleSave() {
     if (!form.title.trim()) {
       Alert.alert("Required", "Title is required.");
@@ -298,6 +316,35 @@ export default function NewIncidentScreen() {
           returnKeyType="next"
         />
 
+        {aiEnabled && form.title.trim() && form.symptom.trim() && (
+          <View style={{ marginBottom: 16 }}>
+            <Pressable
+              onPress={handleSuggest}
+              disabled={suggesting}
+              style={{
+                backgroundColor: suggesting ? Colors.surface2 : Colors.surface,
+                borderRadius: 8,
+                padding: 12,
+                alignItems: "center",
+                borderWidth: 1,
+                borderColor: Colors.primary,
+                flexDirection: "row",
+                justifyContent: "center",
+                gap: 8,
+              }}
+            >
+              <Text style={{ color: Colors.primary, fontSize: 14, fontWeight: "700" }}>
+                {suggesting ? "Analyzing…" : "✦ Suggest root cause & fix"}
+              </Text>
+            </Pressable>
+            {suggestError !== "" && (
+              <Text style={{ color: Colors.danger, fontSize: 12, marginTop: 6 }}>
+                {suggestError}
+              </Text>
+            )}
+          </View>
+        )}
+
         {labelRow("Root Cause", "rootCause")}
         <TextInput
           style={MONO_FIELD_STYLE}