The theoretical foundation of the project is compiled in the main concept ["uchitsya-legko.rf — learning to read as decoding a written code"](/concepts/uchitsya-legko-rf-obuchenie-chteniyu-kak-deshifrovke-pismennogo-koda). It is the central point of the project: it describes the general model, current state, and connects specific concepts.

The project is currently at the **Idea** stage. The basic theory of reading as information reconstruction from a written code has been formed. The information entities on which learning is built have been recorded: object and situation, concept, image, spoken word, sound, written word, letters, and larger structural parts of a word.

Key components of the theory:

- [Reading is word recognition and meaning reconstruction, not sequential letter sounding](/concepts/chtenie-eto-raspoznavanie-slova-i-vosstanovlenie-smysla).
- [A written word connects several representations of the same content](/concepts/pismennoe-slovo-svyazyvaet-neskolko-predstavleniy).
- [Learning to read should go from known supports to the unknown code](/concepts/obuchenie-chteniyu-ot-izvestnyh-opor-k-neizvestnomu-kodu).
- [The oral vocabulary is the recognition base when learning to read](/concepts/ustnyy-slovar-baza-raspoznavaniya-pri-obuchenii-chteniyu).
- [A long word must be revealed through familiar structural parts](/concepts/dlinnoe-slovo-cherez-znakomye-strukturnye-chasti).
- [Hints must gradually disappear as connections are mastered](/concepts/podskazki-dolzhny-postepenno-ischezat).

The practical direction is an interactive system where the child starts with recognizable objects and words, confirms their sound, gets acquainted with the spelling, discovers repeating elements of the written code, and then applies the discovered correspondences to decode new words.

Critical principle: the system must not simultaneously require the mastery of several unknown levels. If the child does not know the concept, the spoken word, its sound, and the letters, such a word is poorly suited as starting material. The next task must rely on the already confirmed knowledge of the specific child.

The next stage of the project is to turn the theory into minimal interactive mechanics and test the main criterion: is the child able to transfer mastered correspondences to previously unseen words, rather than just memorizing shown examples.

An interactive project for teaching reading as the gradual decoding of a written code through meanings, images, and spoken words already familiar to the child.

uchitsya-legko.rf

## Task

Extract the common execution logic of `VoiceScenario` into a single runtime module and use it simultaneously in both the synthesizer and the visualizer.

Currently, the logic for `prepareScenario`, `evaluateBezier`, `updateAutomations`, `executeCommand`, and the computation of the current `VoiceControlState` is essentially duplicated. This creates a risk of divergence: the visualizer might display a state different from the one actually used by the DSP.

## What needs to be done

- Create a shared runtime module for `VoiceScenario` (e.g., `VoiceSynthesizer/src/runtime.ts`).
- Extract the preparation of scenario composition and the general timeline there.
- Extract the interpretation of `set` and `animate`.
- Extract cubic bezier calculation.
- Extract the updating of active automations and the semantics of preserving `to` values after `duration` ends.
- Ensure the ability to obtain the actual `VoiceControlState` over time or iterate the state along the timeline.
- Migrate `synthesizeScenario` to this runtime.
- Migrate `ScenarioVisualizer` to the same runtime so that the chart reflects the actual state of the synthesizer rather than a separate interpretation of the scenario.
- Preserve the existing semantics of scenario array composition: `initial` is present only on the first scenario, while subsequent ones continue the current state without a reset.

## Acceptance Criteria

For the exact same `VoiceScenario`, the synthesizer and the visualizer use the exact same state machine implementation. After changing the runtime semantics, situations where the DSP executes a scenario one way and the visualizer displays it another way become impossible.

Eliminate duplication of VoiceScenario execution logic between synthesizeScenario and ScenarioVisualizer.

Tasks

Extract VoiceScenario runtime into a shared module for synthesizer and visualizer