Remove hardcoded pool mount point mappings for true auto-discovery

- Eliminate hardcoded mappings like 'root' -> '/' and 'steampool' -> '/mnt/steampool'
- Use device names directly for physical drives
- Rely on mount_point metrics from agent for actual mount paths
- Implement zero-configuration architecture as specified in CLAUDE.md

Cargo.lock

@@ -279,7 +279,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.126"
+version = "0.1.127"
 dependencies = [
  "anyhow",
  "chrono",
@@ -301,7 +301,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.126"
+version = "0.1.127"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -324,7 +324,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.126"
+version = "0.1.127"
 dependencies = [
  "chrono",
  "serde",