P2a: eight-bar arrangement with four editable sections

README.md

@@ -2,7 +2,7 @@
 
 Sound is terrain. A sampling instrument where material is cut in a quarry, laid as stones in a nave, and played by a hand or an agent through the same verbs.
 
-This repository is **P1 complete**: the Rust engine, the wire, the descent, the quarry, a project that survives restarts, recording, manual faces and trim, an undo stack that comes back with the project, and a native Tauri window that hosts the engine itself. A found or recorded sound is cut into sixteen faces by hand or by analysis, laid on a vein and heard in the loop; every project edit is autosaved and reversible. The next phase is the arrangement and the agent. The visual demo in [`reference/demo`](reference/demo) remains a design reference, not the codebase. The roadmap is in [`docs/PLAN.md`](docs/PLAN.md).
+This repository is **P2 in progress**: the engine, the wire, the descent, the quarry, a persistent project, recording, manual faces, undo across restarts, a native host — and an **8-bar arrangement of four sections**. A found or recorded sound is cut into sixteen faces, laid on a vein, arranged across A–D, and heard as an eight-bar loop; the render and the agent are the remaining P2 slices. The visual demo in [`reference/demo`](reference/demo) remains a design reference, not the codebase. The roadmap is in [`docs/PLAN.md`](docs/PLAN.md).
 
 ![The quarry](preview-p1-quarry.png)
 
@@ -16,6 +16,8 @@ This repository is **P1 complete**: the Rust engine, the wire, the descent, the
 
 ![P1d · a cut and trimmed core](preview-p1d-faces.png)
 
+![P2 · eight bars, four sections](preview-p2-arrangement.png)
+
 ## What is real
 
 - **Rust engine.** `cpal` output at 48 kHz, five veins, a sixteen-step phrase, a fixed voice pool, per-vein levels and gains, a bar clock. Procedural voices for empty pattern rows; real sample voices for rows with a face. No Web Audio.
@@ -29,6 +31,7 @@ This repository is **P1 complete**: the Rust engine, the wire, the descent, the
 - **Session + journal.** Validation, revisions, a journal for project edits (tempo, gains, pattern faces and steps); play, stop and strikes are performance, not history.
 - **Surface.** A Svelte 5 descent whose terrain, eye, city, road, stones and playhead react to the five levels and the master; a real wire log; engine facts; cilia; a master signal trace; vein gains; transport; keyboard.
 - **Native host.** The Tauri app starts the same host inside its own process: engine, session, SQLite project, assets and loopback wire. The built window is self-contained; the browser path uses the standalone daemon. One process owns `127.0.0.1:4317` at a time.
+- **Arrangement.** Four 2-bar sections (A–D) make an 8-bar loop. The engine plays the sections in order; the descent draws all eight bars with section seams and letters; the quarry edits the active section, selects, copies and clears. The sections, the active section and their edits are persisted and undoable; the pattern rows and faces stay per section.
 - **Verification.** Rust unit tests, a live wire test, a material import test, a browser quarry test and the P0 regression smoke, plus `svelte-check` and a production build.
 
 The Tauri 2 app is **built and running with its own engine**: the native window loads the embedded surface and the host starts the engine, session, project and wire in the app process. It is built with Tauri 2.12.5 / CLI 2.12.4 against WebKitGTK 2.54.2, GTK 3.24.52 and dbus 1.16.2. The binary is `app/src-tauri/target/release/zhila-app` (14 MB); installers are a later step.
@@ -101,13 +104,19 @@ npm --prefix ui run quarry-smoke      # daemon + Vite: import, assign, play, scr
 npm --prefix ui run project-smoke     # daemon + Vite: project, undo, import, screenshots
 npm --prefix ui run record-smoke      # daemon + Vite: fake microphone take, faces, seal
 npm --prefix ui run faces-smoke       # daemon + Vite: drag a seam, trim, save, screenshot
+npm --prefix ui run arrangement-smoke # daemon + Vite: sections, edit B, 8-bar descent
 cd app && ./node_modules/.bin/tauri build --no-bundle   # native app with the embedded host
 npm --prefix ui run restored-smoke    # after restarting the daemon on the saved project
 ```
 
 `npm --prefix ui run smoke` writes `preview-p0*.png`; `quarry-smoke` writes `preview-p1-*.png`.
 
-## P1 limits (next, not hidden)
+## P2 limits (in progress, not hidden)
+
+- The arrangement is exactly four 2-bar sections; no section length, reorder, insert or per-section mute yet.
+- Render and the agent are the next P2 slices; they are not in this commit.
+
+## P1 limits (kept honest)
 
 - Recording is mono, 16-bit, requested 48 kHz, up to 30 s, no monitoring and no input device choice. WebKitGTK/Tauri microphone permission is untested; the browser path is verified with Chromium's fake capture.
 - Face editing is seventeen contiguous cuts: no zoom, fades or per-face loop points. The trim is the outer pair of cuts; the source bytes are untouched.
@@ -120,4 +129,4 @@ npm --prefix ui run restored-smoke    # after restarting the daemon on the saved
 - No agent/MCP in this phase.
 - The Tauri shell now builds and runs; the engine is still the separate daemon (embedding is next).
 
-P1 is complete at the "first playing loop" milestone: material, sampler, project, recording, cutting, history and the native host. The next phase is P2: the arrangement across bars, render to WAV, and the agent on the same verbs. The plan is in [`docs/PLAN.md`](docs/PLAN.md); the phase notes are in [`docs/P1.md`](docs/P1.md).
+P2 is the arrangement, the offline WAV render and the in-app agent. P2a (the arrangement) is in this tree; P2b and P2c follow. The plan is in [`docs/PLAN.md`](docs/PLAN.md); the phase notes are in [`docs/P2.md`](docs/P2.md). The plan is in [`docs/PLAN.md`](docs/PLAN.md); the phase notes are in [`docs/P1.md`](docs/P1.md).