feat: add customizable uptime display with multiple time units

[NightWatcher314]

Summary

• Add new uptime module with flexible time unit support (week, day, hour, min, sec)
• Implement intelligent unit sorting and carry-over logic
• Move uptime from system stats to dedicated --uptime flag
• Support custom unit combinations (e.g., --uptime day min)
• Update CLI to include --uptime flag with unit validation
• Update README with correct uptime usage examples

Changes

• Created new src/stats/uptime.rs module with customizable time unit display
• Modified CLI to add --uptime flag with proper validation
• Updated system stats to remove uptime (now handled separately)
• Fixed README examples to show correct space-separated flag syntax

Test plan

• Verify --uptime flag works with various unit combinations
• Confirm README examples match actual CLI behavior
• Test backward compatibility with existing functionality

[Copilot]

Pull Request Overview

This PR introduces a customizable uptime display system that allows users to specify which time units to show (week, day, hour, min, sec) and moves uptime functionality from system stats to a dedicated --uptime flag.

• Created a new uptime module with flexible time unit support and intelligent carry-over logic
• Added --uptime CLI flag with proper validation and removed uptime from system stats
• Updated documentation to reflect the new uptime usage patterns

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/stats/uptime.rs	New module implementing customizable uptime display with multiple time units
src/stats/system.rs	Removed uptime handling from system stats
src/stats/mod.rs	Added uptime module export
src/main.rs	Integrated new uptime flag handling and removed old uptime logic
src/cli.rs	Added --uptime flag and removed uptime from system flags
README.md	Updated documentation with new uptime usage examples

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[Copilot]

The uptime flags are not sorted in the same order as TIME_UNITS in uptime.rs (week, day, hour, min, sec). This inconsistency could be confusing. Consider ordering them consistently, either largest-to-smallest or alphabetically.

Suggested change

	vec!["day", "hour", "min", "sec", "week"]
	vec!["week", "day", "hour", "min", "sec"]

[Copilot]

Using unwrap_or(usize::MAX) could place invalid flags at the end of the sorted list instead of handling them properly. Invalid flags should be filtered out or cause an error, as they won't match any TIME_UNITS entry and will be silently ignored in the following loop.

[joncrangle]

Could use the following to filter out invalid flags:

    let sorted_flags: Vec<&str> = if flags.is_empty() {
        TIME_UNITS.iter().map(|u| u.name).collect()
    } else {
        let mut flags_vec: Vec<&str> = flags
            .iter()
            .copied()
            .filter(|&flag| TIME_UNITS.iter().any(|u| u.name == flag))
            .collect();

        flags_vec.sort_by_key(|&flag| TIME_UNITS.iter().position(|u| u.name == flag).unwrap());
        flags_vec
    };

[joncrangle]

Thanks for the PR. I've tested and works great. Please address the two review comments and I'll merge. Please run cargo fmt and cargo clippy to make sure it will pass CI.

[NightWatcher314]

Apologies for the delayed response. I’ve been quite busy the past couple of days and unfortunately missed replying to this PR. I’ll now make the necessary changes as per your suggestions and get them updated shortly.