Implement complete structured data architecture

Replace fragile string-based metrics with type-safe JSON data structures.
Agent converts all metrics to structured data, dashboard processes typed fields.

Changes:
- Add AgentData struct with CPU, memory, storage, services, backup fields
- Replace string parsing with direct field access throughout system
- Maintain UI compatibility via temporary metric bridge conversion
- Fix NVMe temperature display and eliminate string parsing bugs
- Update protocol to support structured data transmission over ZMQ
- Comprehensive metric type coverage: CPU, memory, storage, services, backup

Version bump to 0.1.131

CLAUDE.md

@@ -59,11 +59,85 @@ hostname2 = [
 
 ## Core Architecture Principles
 
-### Individual Metrics Philosophy
-- Agent collects individual metrics, dashboard composes widgets
-- Each metric collected, transmitted, and stored individually
-- Agent calculates status for each metric using thresholds
-- Dashboard aggregates individual metric statuses for widget status
+### Structured Data Architecture (Planned Migration)
+Current system uses string-based metrics with complex parsing. Planning migration to structured JSON data to eliminate fragile string manipulation.
+
+**Current (String Metrics):**
+- Agent sends individual metrics with string names like `disk_nvme0n1_temperature`
+- Dashboard parses metric names with underscore counting and string splitting
+- Complex and error-prone metric filtering and extraction logic
+
+**Target (Structured Data):**
+```json
+{
+  "hostname": "cmbox",
+  "agent_version": "v0.1.130",
+  "timestamp": 1763926877,
+  "system": {
+    "cpu": {
+      "load_1min": 3.50,
+      "load_5min": 3.57,
+      "load_15min": 3.58,
+      "frequency_mhz": 1500,
+      "temperature_celsius": 45.2
+    },
+    "memory": {
+      "usage_percent": 25.0,
+      "total_gb": 23.3,
+      "used_gb": 5.9,
+      "swap_total_gb": 10.7,
+      "swap_used_gb": 0.99,
+      "tmpfs": [
+        {"mount": "/tmp", "usage_percent": 15.0, "used_gb": 0.3, "total_gb": 2.0}
+      ]
+    },
+    "storage": {
+      "drives": [
+        {
+          "name": "nvme0n1",
+          "health": "PASSED",
+          "temperature_celsius": 29.0,
+          "wear_percent": 1.0,
+          "filesystems": [
+            {"mount": "/", "usage_percent": 24.0, "used_gb": 224.9, "total_gb": 928.2}
+          ]
+        }
+      ],
+      "pools": [
+        {
+          "name": "srv_media",
+          "mount": "/srv/media",
+          "type": "mergerfs",
+          "health": "healthy",
+          "usage_percent": 63.0,
+          "used_gb": 2355.2,
+          "total_gb": 3686.4,
+          "data_drives": [
+            {"name": "sdb", "temperature_celsius": 24.0}
+          ],
+          "parity_drives": [
+            {"name": "sdc", "temperature_celsius": 24.0}
+          ]
+        }
+      ]
+    }
+  },
+  "services": [
+    {"name": "sshd", "status": "active", "memory_mb": 4.5, "disk_gb": 0.0}
+  ],
+  "backup": {
+    "status": "completed",
+    "last_run": 1763920000,
+    "next_scheduled": 1764006400,
+    "total_size_gb": 150.5,
+    "repository_health": "ok"
+  }
+}
+```
+- Agent sends structured JSON over ZMQ
+- Dashboard accesses data directly: `data.system.storage.drives[0].temperature_celsius`
+- Type safety eliminates all parsing bugs
+
 
 ### Maintenance Mode
 - Agent checks for `/tmp/cm-maintenance` file before sending notifications
@@ -293,12 +367,33 @@ Keep responses concise and focused. Avoid extensive implementation summaries unl
 - ✅ "Restructure storage widget with improved layout"
 - ✅ "Update CPU thresholds to production values"
 
+## Planned Architecture Migration
+
+### Phase 1: Structured Data Types (Shared Crate)
+- Create Rust structs matching target JSON structure
+- Replace `Metric` enum with typed data structures  
+- Add serde serialization/deserialization
+
+### Phase 2: Agent Refactor
+- Update collectors to return typed structs instead of `Vec<Metric>`
+- Remove string metric name generation
+- Send structured JSON over ZMQ
+
+### Phase 3: Dashboard Refactor
+- Replace metric parsing logic with direct field access
+- Remove `extract_pool_name()`, `extract_drive_name()`, underscore counting
+- Widgets access `data.system.storage.drives[0].temperature_celsius`
+
+### Phase 4: Migration & Cleanup
+- Support both formats during transition
+- Gradual rollout with backward compatibility
+- Remove legacy string metric system
+
 ## Implementation Rules
 
-1. **Individual Metrics**: Each metric is collected, transmitted, and stored individually
-2. **Agent Status Authority**: Agent calculates status for each metric using thresholds
-3. **Dashboard Composition**: Dashboard widgets subscribe to specific metrics by name
-4. **Status Aggregation**: Dashboard aggregates individual metric statuses for widget status
+1. **Agent Status Authority**: Agent calculates status for each metric using thresholds
+2. **Dashboard Composition**: Dashboard widgets subscribe to specific metrics by name
+3. **Status Aggregation**: Dashboard aggregates individual metric statuses for widget status
 
 **NEVER:**
 - Copy/paste ANY code from legacy implementations