feat: add copy command

[notnmeyer]

adds a copy subcommand that copies the specified log to the clipboard.

supports all the same log selection stuff. daylog copy copies today's log,

# 2025/06/10

TODAY

similarly, logs from past/future work too,
daylog copy -- tomorrow,

# 2025/06/11

TOMORROW

closes #48

---

also bumps go to 1.24

[notnmeyer]

blarg, golang.design/x/clipboard uses x11 and blows up under wayland on linux. sounds like clipboard access at the cli is a bit of a nightmare on linux.

[notnmeyer]

other options look equally bad. this will work.

[Copilot]

Pull Request Overview

This PR introduces a new copy subcommand for copying logs to the clipboard and updates the environment/tooling to Go 1.24.

• Adds a copy CLI command using the golang.design/x/clipboard package
• Bumps Go versions across go.mod, shell.nix, and CI workflows to 1.24 and installs necessary system deps
• Refactors task definitions in tasks.toml and updates the README with Linux build notes

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tasks.toml	Flattened multi-line cmds arrays and added a new:command task
shell.nix	Updated Go to 1.24, added nativeBuildInputs and X11 in buildInputs
go.mod	Upgraded Go to 1.24, added golang.design/x/clipboard dependency
cmd/copy.go	Implemented the new copy command
README.md	Revised source install section and noted X11 header requirement
.github/workflows/test.yml	Updated Go version, installed X11 headers
.github/workflows/release.yml	Updated Go version, installed X11 headers

Comments suppressed due to low confidence (4)

cmd/copy.go:36

• [nitpick] The function name "copy" shadows the built-in Go function and is ambiguous; consider renaming it to "copyToClipboard" for clarity.

func copy(content []byte) error {

.github/workflows/test.yml:15

• The CI step installs only X11 headers but misses required build tools (gcc and pkg-config) needed for the clipboard dependency; add them to the apt-get install command.

      - run: sudo apt-get install libx11-dev

.github/workflows/release.yml:23

• Similar to the test workflow, this step should also install gcc and pkg-config alongside libx11-dev to ensure successful builds with the clipboard package.

      - run: sudo apt-get install libx11-dev

go.mod:41

• [nitpick] This indirect dependency appears to be pulled in transitively; consider removing explicit require lines for indirect modules and letting 'go mod tidy' handle them.

    golang.org/x/exp/shiny v0.0.0-20250606033433-dcc06ee1d476 // indirect