feat(settings): per-model effort and turn presets

ClaudeDo never passed --effort, so every session inherited whatever effortLevel
the user's Claude Code config happened to carry. Settings -> General now holds one
row per model alias (haiku medium/20, sonnet high/30, opus high/40, fable high/25)
supplying the global effort and turn defaults; list- and task-level max-turns
overrides still win, and the agent editor's inherited badge follows the model.

--effort is applied to autonomous runs and to every ConPTY spec (task session,
planning start/resume, ad-hoc, list handler). The model itself is deliberately not
forced on interactive sessions. The single global 'Max turns' field is replaced by
the table, and 'fable' joins ModelRegistry.Aliases.

The migration also adds the is_manual columns used by the next commit.

src/ClaudeDo.Data/Models/AppSettingsEntity.cs

@@ -30,4 +30,8 @@ public sealed class AppSettingsEntity
 
     // JSON array of session skill names applied by default to new tasks.
     public string? SessionSkills { get; set; }
+
+    // JSON array of ModelPreset rows (model → effort + max turns). Supplies the global effort and
+    // turn defaults per model; list-/task-level max-turns overrides still win. Null = ship defaults.
+    public string? ModelPresets { get; set; }
 }