Remove unused task metrics feature

[Copilot]

The metrics collection feature (memory usage via ps/procfs) was fully wired up but never consumed by anything meaningful. Removes the entire code path end-to-end.

Removed

• internal/types/metrics.go — Metrics struct
• internal/metrics/ package — ps and procfs memory parsing helpers
• GetMetrics(ctx) (*types.Metrics, error) from proc.Interface and all implementations (host, container, k8s, noop), including k8s private helpers (getMetrics, getContainersInPod, getContainerMetrics)
• 20-second polling goroutine in internal/run.go that called p.GetMetrics and stuffed results onto node.Metrics
• Metrics field from TaskNode

UI (internal/index.html)

• Removed #metrics CSS rule, <span id="metrics"> DOM element, formatMetrics() JS function, and all node.metrics data bindings in both the initial graph render and SSE update paths

Docs

• Removed "real-time metrics" from the Web UI feature description in README.md

[alexec]

@copilot fix conflicts.

[Copilot]

Pull request overview

Removes the previously implemented (but unused) task memory metrics pipeline end-to-end, including backend collection/parsing, propagation through TaskNode, and Web UI rendering, and updates documentation to match.

Changes:

• Removed types.Metrics, the internal/metrics parsing helpers, and GetMetrics from the proc.Interface plus all implementations.
• Removed the periodic metrics polling goroutine and eliminated the TaskNode.Metrics field.
• Removed all metrics-related UI bindings/CSS/formatting and updated README to no longer claim “real-time metrics”.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
README.md	Updates Web UI feature description to remove “real-time metrics” claim.
internal/types/metrics.go	Deletes the Metrics struct type.
internal/task_node.go	Removes TaskNode.Metrics JSON field.
internal/run.go	Removes the 20s polling goroutine that collected/published metrics.
internal/proc/proc.go	Removes GetMetrics from the proc.Interface.
internal/proc/noop.go	Removes the noop metrics implementation and related import.
internal/proc/kubernetes.go	Removes Kubernetes metrics aggregation/helpers and related imports/comments.
internal/proc/host.go	Removes host ps-based metrics collection and related import.
internal/proc/container.go	Removes container procfs metrics collection and related import.
internal/metrics/ps.go	Deletes ps parsing helpers.
internal/metrics/procfs.go	Deletes procfs parsing helpers.
internal/index.html	Removes metrics DOM element, CSS, formatter, and data bindings in initial render + SSE updates.

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[Copilot]

@copilot fix conflicts.

Conflicts are fixed in commit 83f61eb. I merged origin/main into this branch and resolved the merge issues while keeping the metrics-removal changes intact.