Move C-state name cleaning to agent for smaller JSON

- Agent now extracts "C" + digits pattern (C3, C10) using char parsing
- Removes suffixes like "_ACPI", "_MWAIT" at source
- Reduces JSON payload size over ZMQ
- No regex dependency - uses fast char iteration (~1μs overhead)
- Robust fallback to original name if pattern not found
- Dashboard simplified to use clean names directly

Bump version to v0.1.212

Co-Authored-By: Claude <noreply@anthropic.com>

agent/src/collectors/cpu.rs

@@ -135,10 +135,23 @@ impl CpuCollector {
             if let Ok(time_str) = utils::read_proc_file(&time_path) {
                 if let Ok(time) = utils::parse_u64(time_str.trim()) {
                     if let Ok(name) = utils::read_proc_file(&name_path) {
-                        let state_name = name.trim().to_string();
+                        let state_name = name.trim();
                         // Skip POLL state (not real idle)
                         if state_name != "POLL" && time > 0 {
-                            cstate_times.push((state_name, time));
+                            // Extract "C" + digits pattern (C3, C10, etc.) to reduce JSON size
+                            // Handles formats like "C3_ACPI", "C10_MWAIT", etc.
+                            let clean_name = if let Some(c_pos) = state_name.find('C') {
+                                let rest = &state_name[c_pos + 1..];
+                                let digit_count = rest.chars().take_while(|c| c.is_ascii_digit()).count();
+                                if digit_count > 0 {
+                                    state_name[c_pos..c_pos + 1 + digit_count].to_string()
+                                } else {
+                                    state_name.to_string()
+                                }
+                            } else {
+                                state_name.to_string()
+                            };
+                            cstate_times.push((clean_name, time));
                             total_time += time;
                         }
                     }