fix(worker): normalize model alias before preset lookup, wire DefaultMaxTurns as fallback

A full model id like claude-sonnet-4-6 in list_config.model never matched any
ModelPresets row (only bare aliases did), so every run under it landed on the
hardcoded 30-turn/DefaultLevel fallback instead of the sonnet preset row -
this is what killed two autonomous tasks at the 30-turn limit.

ModelRegistry.TryNormalizeAlias (non-throwing: exact match, then substring
match against a full model id) lets ModelPresets.For resolve a full model id
to its alias's preset row. For a model that still doesn't resolve, the
hardcoded 30 is replaced by a caller-supplied fallbackMaxTurns, and TaskRunner
now passes AppSettings.DefaultMaxTurns there - so that setting has a real
effect instead of being dead, matching the direction already noted in
docs/open.md.

src/ClaudeDo.Data/Models/ModelPresets.cs

@@ -46,20 +46,26 @@ public static class ModelPresets
     }
 
     /// <summary>The preset for <paramref name="model"/>, or the default row for it. Never null so
-    /// callers don't have to special-case an unconfigured or unknown model.</summary>
-    public static ModelPreset For(IReadOnlyList<ModelPreset> presets, string? model)
+    /// callers don't have to special-case an unconfigured or unknown model. <paramref name="model"/>
+    /// is resolved through <see cref="ModelRegistry.TryNormalizeAlias"/> first, so a full CLI model
+    /// id (e.g. "claude-sonnet-4-6") still hits its alias's preset row instead of falling through.
+    /// If <paramref name="model"/> normalizes to nothing recognized, <paramref name="fallbackMaxTurns"/>
+    /// (typically <c>AppSettings.DefaultMaxTurns</c>) is used instead of a hardcoded number, so a
+    /// truly unknown model is no harsher than the configured global default.</summary>
+    public static ModelPreset For(IReadOnlyList<ModelPreset> presets, string? model, int fallbackMaxTurns = 30)
     {
-        var alias = (model ?? ModelRegistry.DefaultAlias).Trim();
+        var alias = ModelRegistry.TryNormalizeAlias(model) ?? (model ?? ModelRegistry.DefaultAlias).Trim();
         foreach (var p in presets)
             if (string.Equals(p.Model, alias, StringComparison.OrdinalIgnoreCase))
                 return p;
         foreach (var p in Defaults)
             if (string.Equals(p.Model, alias, StringComparison.OrdinalIgnoreCase))
                 return p;
-        return new ModelPreset(alias, EffortRegistry.DefaultLevel, 30);
+        return new ModelPreset(alias, EffortRegistry.DefaultLevel, fallbackMaxTurns);
     }
 
-    public static ModelPreset For(string? json, string? model) => For(Parse(json), model);
+    public static ModelPreset For(string? json, string? model, int fallbackMaxTurns = 30)
+        => For(Parse(json), model, fallbackMaxTurns);
 
     // One row per known alias, canonical order, clamped values — so an edited or partial list
     // still round-trips into something every consumer can rely on.

src/ClaudeDo.Data/Models/ModelRegistry.cs

@@ -26,4 +26,22 @@ public static class ModelRegistry
                 return alias;
         throw new ArgumentException($"Unknown model '{model}'. Allowed: {string.Join(", ", Aliases)}.");
     }
+
+    /// <summary>
+    /// Best-effort alias lookup for run-path model resolution, where a full CLI model id
+    /// (e.g. "claude-sonnet-4-6") is just as likely as a bare alias and a run must never be
+    /// blocked by an unrecognized one. Null/blank/unrecognized → null; never throws.
+    /// </summary>
+    public static string? TryNormalizeAlias(string? model)
+    {
+        var m = model?.Trim();
+        if (string.IsNullOrEmpty(m)) return null;
+        foreach (var alias in Aliases)
+            if (string.Equals(alias, m, StringComparison.OrdinalIgnoreCase))
+                return alias;
+        foreach (var alias in Aliases)
+            if (m.Contains(alias, StringComparison.OrdinalIgnoreCase))
+                return alias;
+        return null;
+    }
 }