refactor: simplify event API method names for better ergonomics

- Rename verbose method names to shorter, clearer alternatives
- program_received_time_us() → recv_us()
- program_handle_time_consuming_us() → handle_us()
- instruction_outer_index() → outer_index()
- instruction_inner_index() → inner_index()
- Update all implementations across event parsers and processors

Improves developer experience while maintaining semantic clarity.

src/streaming/event_parser/protocols/block/block_meta_event.rs

@@ -18,7 +18,7 @@ impl BlockMetaEvent {
         slot: u64,
         block_hash: String,
         block_time_ms: i64,
-        program_received_time_us: i64,
+        recv_us: i64,
     ) -> Self {
         let metadata = EventMetadata::new(
             Signature::default(),
@@ -30,7 +30,7 @@ impl BlockMetaEvent {
             solana_sdk::pubkey::Pubkey::default(),
             0,
             None,
-            program_received_time_us,
+            recv_us,
             None,
         );
         Self { metadata, slot, block_hash }