feat: add eyre + color-eyre for rich error reporting

[getappz]

Closes #37 (partial)

Summary

Add eyre + color-eyre dependencies and install color_eyre error handler at program start for color-coded errors with backtraces and source context — matches mise's error reporting pattern.

Test plan

• \cargo check\ passes
• \cargo build\ compiles

Notes for reviewers

• Risk areas: color_eyre::install() panics on failure — same as mise's pattern
• Backwards compatibility: additive, no breaking API changes

Summary by CodeRabbit

• New Features
  • Improved error reporting at startup, making failures easier to understand and diagnose.
  • Added support for richer, more readable error messages throughout the app.

[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between e90c6fa and 7b40f59.

📒 Files selected for processing (2)

• Cargo.toml
• src/main.rs

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📝 Walkthrough

Walkthrough

Adds eyre and color-eyre crates as dependencies in Cargo.toml and installs the color_eyre error handler at the start of main(), before CLI argument parsing.

Changes

Error Reporting Setup

Layer / File(s)	Summary
Dependency and handler installation Cargo.toml, src/main.rs	Adds eyre and color-eyre dependencies and installs color_eyre::install() in main() prior to Cli::parse(), panicking on install failure.

Estimated code review effort: 1 (Trivial) | ~3 minutes

Related issues: #37 (partial — adds eyre/color-eyre for rich error reporting; other checklist items such as build.rs, edition 2024, thiserror migration, and tooling config remain unaddressed)

Suggested labels: dependencies, enhancement

Suggested reviewers: none identified

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The PR implements the #37 objective to add eyre/color-eyre rich error reporting, and the remaining checklist items are out of scope.
Out of Scope Changes check	✅ Passed	The diff only adds eyre/color-eyre support and startup installation, with no unrelated changes visible.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Title check	✅ Passed	The title is concise and accurately summarizes the main change: adding eyre/color-eyre for richer error reporting.
Description check	✅ Passed	The description includes summary, test plan, and reviewer notes, matching the template; only the checklist formatting is slightly different.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch worktree-mise-eyre

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