Add timeout parameter to metadata_server and chunk_server init/step functions

Unified the function signatures across all process types (metadata server,
chunk server, and simulation client) to accept an int *timeout parameter.
This provides consistency in the simulation framework and allows all
process types to control their wakeup times.

**Changes:**

**Headers (metadata_server.h, chunk_server.h):**
- Updated metadata_server_init() to accept int *timeout parameter
- Updated metadata_server_step() to accept int *timeout parameter
- Updated chunk_server_init() to accept int *timeout parameter
- Updated chunk_server_step() to accept int *timeout parameter

**Implementations (metadata_server.c, chunk_server.c):**
- Modified init functions to set *timeout = -1 (no timeout needed)
- Modified step functions to set *timeout = -1 (no timeout needed)
- Both server types currently don't require periodic wakeups, but the
  parameter allows for future timeout-based behavior

**System Integration (system.c):**
- Updated spawn_simulated_process() to declare timeout variable once
  and pass it to all process init functions uniformly
- Updated update_simulation() to declare timeout variable once and
  pass it to all process step functions uniformly
- Simplified control flow by removing special case for client timeout
  handling - now all process types use the same timeout logic
- Consolidated timeout-to-wakeup_time conversion after switch statements

**Benefits:**
- Consistent API across all process types
- Cleaner code with reduced duplication
- Future-proof for server timeout requirements
- All processes now managed uniformly by simulation framework

The simulation continues to run correctly with all process types
handling timeout parameter appropriately.

src/metadata_server.c

@@ -750,7 +750,7 @@ static bool is_chunk_server_message_type(uint16_t type)
     return false;
 }
 
-int metadata_server_init(MetadataServer *state, int argc, char **argv, void **contexts, struct pollfd *polled)
+int metadata_server_init(MetadataServer *state, int argc, char **argv, void **contexts, struct pollfd *polled, int *timeout)
 {
     (void) argc;
     (void) argv;
@@ -778,6 +778,7 @@ int metadata_server_init(MetadataServer *state, int argc, char **argv, void **co
         return -1;
     }
 
+    *timeout = -1;  // No timeout needed for metadata server
     return tcp_register_events(&state->tcp, contexts, polled);
 }
 
@@ -788,7 +789,7 @@ int metadata_server_free(MetadataServer *state)
     return 0;
 }
 
-int metadata_server_step(MetadataServer *state, void **contexts, struct pollfd *polled, int num_polled)
+int metadata_server_step(MetadataServer *state, void **contexts, struct pollfd *polled, int num_polled, int *timeout)
 {
     Event events[MAX_CONNS+1];
     int num_events = tcp_translate_events(&state->tcp, events, contexts, polled, num_polled);
@@ -852,5 +853,6 @@ int metadata_server_step(MetadataServer *state, void **contexts, struct pollfd *
         }
     }
 
+    *timeout = -1;  // No timeout needed for metadata server
     return tcp_register_events(&state->tcp, contexts, polled);
 }