feature: add disk I/O time series chart

[ClementTsang]

Description

A description of the change, what it does, and why it was made. If relevant (e.g. UI changes), please also provide screenshots/recordings:

This PR adds a disk I/O (read and write rate) graph. This partially handles #205, with a disk usage graph to also come.

Issue

If applicable, what issue does this address?

Partially tackles #205.

Testing

If relevant, please state how this was tested (including steps):

If this change affects the program, please also indicate which platforms were tested:

• Windows
• macOS (specify version below)
• Linux (specify distro below)
• Other (specify below)

Checklist

Ensure all of these are met:

• If this PR adds or changes a dependency, please justify this in the description
• If this is a code change, areas your change affects have been linted using (cargo fmt)
• If this is a code change, your changes pass cargo clippy --all -- -D warnings
• If this is a code change, new tests were added if relevant
• If this is a code change, your changes pass cargo test
• The change has been tested to work (see above) and doesn't appear to break other things
• Documentation has been updated if needed (README.md, help menu, docs, configs, etc.)
• There are no merge conflicts
• You have reviewed your changes first
• The pull request passes the provided CI pipeline

Other

Anything else that maintainers should know about this PR:

[codecov]

Codecov Report

❌ Patch coverage is 24.05660% with 322 lines in your changes missing coverage. Please review.
✅ Project coverage is 61.87%. Comparing base (7d9b710) to head (c913ade).

Files with missing lines	Patch %	Lines
src/canvas/widgets/disk_io_graph.rs	0.00%	222 Missing ⚠️
src/app/data/time_series.rs	0.00%	37 Missing ⚠️
src/options.rs	35.41%	31 Missing ⚠️
src/widgets/disk_io_graph.rs	0.00%	12 Missing ⚠️
src/canvas.rs	0.00%	7 Missing ⚠️
src/app.rs	0.00%	5 Missing ⚠️
src/app/states.rs	50.00%	3 Missing ⚠️
src/app/data/store.rs	60.00%	2 Missing ⚠️
src/options/config/style.rs	50.00%	2 Missing ⚠️
src/app/layout_manager.rs	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2073      +/-   ##
==========================================
- Coverage   62.48%   61.87%   -0.62%     
==========================================
  Files         130      132       +2     
  Lines       18756    19123     +367     
==========================================
+ Hits        11720    11832     +112     
- Misses       7036     7291     +255     

Flag	Coverage Δ
macos-14	49.54% <23.11%> (-0.81%)	⬇️
ubuntu-24.04	60.84% <24.05%> (-0.63%)	⬇️
windows-2022	49.27% <23.11%> (-0.81%)	⬇️

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