Reorganise by feature, rename to Novelly, add Aspire and a pre-push hook

The layered split into Domain/Application/Infrastructure/Api was forcing
organisation by layer: adding one capability meant touching four projects and
four folders that each held a slice of it. Those four projects are now one
feature-organised Novelly.Api, where each folder — Projects, Characters,
Chapters, Beats, Scenes, Tags, Agent — holds its entity, DTOs, service and
endpoints together. Common/ holds what genuinely crosses features (the patch
semantics, the two exception types, DraftStatus) and Data/ holds the DbContext
and migrations.

Six .NET projects become five: the three layer projects are gone, and
Novelly.AppHost and Novelly.ServiceDefaults are new.

- Namespaces move from NovelSoftware.* to Novelly.*, including the entity type
  names recorded in the EF model snapshots. The migration ids are untouched, so
  an existing novel.db still migrates cleanly — verified against a fresh file.
- Aspire orchestration mirrors the mic-check setup: the AppHost starts the API
  on :5080 and the Vite dev server on :5173, and the API picks up OpenTelemetry,
  health checks and service discovery from ServiceDefaults. /health and /alive
  now answer in development.
- A Husky pre-push hook runs scripts/ci/prepush.sh: build, test, then a web
  build. The scripts are plain bash so CI can run the same steps.
- The MCP server's env var is now NOVELLY_API_URL.

Verified beyond the build: 44 tests pass, the web client builds, the API was
exercised over curl (project/chapter/beat/tag round trip, tag cross-reference,
503 on the agent without a key while conversation listing still returns 200),
the MCP server was driven over stdio JSON-RPC (26 tools, errors still surface
the API's own message rather than being flattened), and the AppHost was run to
confirm both resources come up and Vite proxies /api through to the API.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S56bfZMGe1hnhpWP4CjjNw

src/Novelly.Api/Chapters/Chapter.cs

@@ -0,0 +1,47 @@
+using Novelly.Api.Beats;
+using Novelly.Api.Characters;
+using Novelly.Api.Common;
+using Novelly.Api.Projects;
+using Novelly.Api.Scenes;
+using Novelly.Api.Tags;
+
+namespace Novelly.Api.Chapters;
+
+/// <summary>A chapter: an ordered container of scenes plus its own planning fields.</summary>
+public class Chapter
+{
+    public Guid Id { get; set; } = Guid.NewGuid();
+    public Guid ProjectId { get; set; }
+    public Project? Project { get; set; }
+
+    /// <summary>Position in the manuscript, 1-based.</summary>
+    public int Number { get; set; }
+
+    public string Title { get; set; } = string.Empty;
+
+    /// <summary>
+    /// The paragraph that opens the chapter's outline, above the beat table.
+    /// </summary>
+    public string? Summary { get; set; }
+
+    /// <summary>Whose head we are in for this chapter.</summary>
+    public Guid? PovCharacterId { get; set; }
+    public Character? PovCharacter { get; set; }
+
+    public string? Setting { get; set; }
+    public string? Notes { get; set; }
+
+    public DraftStatus Status { get; set; } = DraftStatus.Planned;
+    public int? TargetWordCount { get; set; }
+
+    public DateTimeOffset CreatedAt { get; set; } = DateTimeOffset.UtcNow;
+    public DateTimeOffset UpdatedAt { get; set; } = DateTimeOffset.UtcNow;
+
+    /// <summary>The chapter's outline: an ordered, flat list of beats.</summary>
+    public List<Beat> Beats { get; set; } = [];
+
+    /// <summary>The prose layer. Beats may optionally be grouped under these.</summary>
+    public List<Scene> Scenes { get; set; } = [];
+
+    public List<Tag> Tags { get; set; } = [];
+}