update and add number theory page

readme

@@ -41,25 +41,30 @@ Use this companion repository for downloadable decks:
 Typical flow:
 
 1. Clone the deck repository somewhere local.
-2. Copy one or more deck folders into `asset/tarot deck/`.
-3. Validate and regenerate the deck registry.
+2. Copy a deck folder into `asset/tarot deck/` (repeat for more decks as needed).
+3. Start the app to pick up the deck list.
 
 ```powershell
 git clone https://code.glowers.club/goyimnose/tarot-deck.git
-# Copy selected deck folder(s) into Tarot Time deck directory.
-npm run validate:decks
+# Copy a deck folder into asset/tarot deck/.
 npm run start
 ```
 
+Auto-discovery behavior:
+
+- Deck ID is automatically inferred from the deck folder path when possible.
+- Deck name is automatically generated from the ID when no label is provided.
+- Example: `rider-waite-smith` becomes `Rider Waite Smith`.
+
 ## Deck Authoring and Validation
 
-Deck discovery is registry-driven and generated automatically.
+Deck discovery is folder-driven and automatic.
 
 1. Copy `asset/tarot deck/_template/` to a new folder under `asset/tarot deck/`.
-2. Rename the new folder and update its `deck.json`.
-3. Add card image files matching the naming rules in the manifest.
-4. Run `npm run validate:decks` before publishing/testing.
-5. Run `npm run start` (or `npm run generate:decks`) to rebuild `asset/tarot deck/decks.json`.
+2. Rename the folder to the deck ID you want (for example `thoth-crowley`).
+3. Update `deck.json` and add card image files matching the naming rules in the manifest.
+4. `label` in `deck.json` is optional; when omitted, a readable name is auto-generated from the folder-based ID.
+5. Run `npm run start` and confirm the deck appears in Settings → Tarot Deck.
 
 Rules and behavior:
 
@@ -70,15 +75,14 @@ Rules and behavior:
 - Decks can define `cardBack` in `deck.json`; if omitted, `back.webp/png/jpg/jpeg/avif/gif` in the deck root is auto-detected.
 - Manifests may override labels with `nameOverrides` and `minorNameOverrides`.
 - Invalid manifests or missing mapped files are skipped with terminal warnings.
+- If a deck entry does not include an explicit ID, the app derives it from the manifest path/folder.
 
 ## NPM Scripts
 
 | Command | Description |
 | --- | --- |
-| `npm run start` | Generate deck registry, then serve the app locally and open `index.html`. |
+| `npm run start` | Serve the app locally and open `index.html`. |
 | `npm run dev` | Alias of `npm run start`. |
-| `npm run generate:decks` | Rebuild `asset/tarot deck/decks.json`. |
-| `npm run validate:decks` | Strict validation only (no write), exits on manifest/file problems. |
 
 ## Project Links