tax rate, version and compose (#70)

resolves #67

Co-authored-by: johba <johba@harb.eth>
Reviewed-on: https://codeberg.org/johba/harb/pulls/70

web-app/README.md

@@ -46,7 +46,7 @@ Programmatically fills the staking form without requiring fragile UI selectors.
 
 **Parameters:**
 - `amount` (number): Amount of KRK tokens to stake (must be >= minimum stake)
-- `taxRate` (number): Tax rate percentage (must be between 0 and 100)
+- `taxRateIndex` (number): Index of the tax rate option (must match one of the configured options)
 
 **Example:**
 ```typescript
@@ -54,7 +54,7 @@ Programmatically fills the staking form without requiring fragile UI selectors.
 await page.evaluate(async () => {
   await window.__testHelpers.fillStakeForm({
     amount: 100,
-    taxRate: 5.0,
+    taxRateIndex: 2,
   });
 });
 
@@ -66,14 +66,14 @@ await stakeButton.click();
 **Validation:**
 - Throws if amount is below minimum stake
 - Throws if amount exceeds wallet balance
-- Throws if tax rate is outside valid range (0-100)
+- Throws if `taxRateIndex` does not match an available option
 
 **TypeScript Support:**
 Type declarations are available in `env.d.ts`:
 ```typescript
 interface Window {
   __testHelpers?: {
-    fillStakeForm: (params: { amount: number; taxRate: number }) => Promise<void>;
+    fillStakeForm: (params: { amount: number; taxRateIndex: number }) => Promise<void>;
   };
 }
 ```