docs: enhance fuzz testing README with comprehensive guide (#25270)

Co-authored-by: Alex | Interchain Labs <[email protected]>

Author: avorylli

tests/fuzz/README.md

@@ -1,10 +1,51 @@
 # Fuzzing
 
-## Running
+This directory contains fuzz tests for the Cosmos SDK to identify potential bugs, crashes, and security vulnerabilities through automated input generation.
 
-The fuzz tests are in standard [Go format](https://go.dev/doc/fuzz/).
-To run a fuzz test, use the `-fuzz` flag to `go test`. For example:
+## What is Fuzzing?
+
+Fuzzing is a testing technique that automatically generates random inputs to find edge cases, crashes, and unexpected behavior in code. The Go fuzzing framework uses coverage-guided fuzzing to efficiently explore code paths.
+
+## Available Fuzz Tests
+
+The following fuzz tests are available:
+
+- **Crypto HD**: `FuzzCryptoHDNewParamsFromPath`, `FuzzCryptoHDDerivePrivateKeyForPath`
+- **Types**: `FuzzTypesParseTimeBytes`, `FuzzTypesParseDecCoin`, `FuzzTypesParseCoin`, `FuzzTypesVerifyAddressFormat`, `FuzzTypesDecSetString`
+- **Tendermint**: `FuzzTendermintAminoDecodeTime`
+- **Crypto Types**: `FuzzCryptoTypesCompactBitArrayMarshalUnmarshal`
+- **Unknown Proto**: `FuzzUnknownProto`
+
+## Running Fuzz Tests
+
+The fuzz tests use the standard [Go fuzzing format](https://go.dev/doc/fuzz/). To run a specific fuzz test, use the `-fuzz` flag with `go test`:
 
 ```shell
-go test -fuzz FuzzCryptoHDNewParamsFromPath ./tests
+# Run a specific fuzz test
+go test -fuzz FuzzCryptoHDNewParamsFromPath ./tests/fuzz/tests
+
+# Run all fuzz tests
+go test -fuzz . ./tests/fuzz/tests
+
+# Run with time limit (e.g., 30 seconds)
+go test -fuzz FuzzTypesParseTimeBytes -fuzztime 30s ./tests/fuzz/tests
 ```
+
+## Interpreting Results
+
+- **Crashes**: If a fuzz test crashes, it will save the input that caused the crash in the `testdata` directory
+- **Coverage**: Fuzzing automatically tracks code coverage and focuses on unexplored paths
+- **Timeouts**: Long-running fuzz tests can be stopped with `Ctrl+C`
+
+## Requirements
+
+- Go 1.18+ (required for built-in fuzzing support)
+- The `gofuzz` build tag is also supported for compatibility
+
+## Contributing
+
+When adding new fuzz tests:
+1. Follow the naming convention: `Fuzz<Package><Function>`
+2. Include proper error handling and input validation
+3. Add the test to this README
+4. Ensure the test can run for extended periods without crashes