feat: add command aliases for stats

[erics118]

add to config like this:

[stats.command_aliases]
"g" = "git"
"dune te" = "dune runtest"
"dune test" = "dune runtest"

Checks

• I am happy for maintainers to push small adjustments to this PR, to speed up the review cycle
• I have checked that there are no existing pull requests for the same thing

closes #2458

[github-actions]

Fossier: Manual Review Requested

@erics118 is a new contributor. A maintainer should review this PR before merging.

Score Breakdown

Total Score: 62.5/100 | Confidence: 100% | Outcome: REVIEW

Signal	Value	Score	Weight
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public_repos	48	1.00	0.05
contribution_history	48	0.24	0.05
follower_ratio	1.09	0.55	0.05
bot_signals	False	0.50	0.04
open_prs_elsewhere	5	0.38	0.09
closed_prs_elsewhere	5	0.50	0.10
merged_prs_elsewhere	45	1.00	0.08
prior_interaction	0	0.00	0.08
activity_velocity	1	1.00	0.08
pr_content	...	1.00	0.08
commit_email	no_email	0.50	0.04
pr_description	...	0.70	0.05
repo_stars	29907	0.30	0.04
org_membership	0	0.20	0.03
commit_verification	...	1.00	0.04
contributor_stars	10	0.20	0.04

[greptile-apps]

Greptile Summary

This PR adds configurable command aliases to stats calculation. It changes:

• Adds stats.command_aliases to client settings with a default empty map.
• Resolves configured aliases before stats grouping.
• Applies alias resolution to pipeline segments used for command ngrams.
• Keeps unique command counting for full commands and split pipeline parts.

Confidence Score: 4/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
crates/atuin-client/src/settings.rs	Adds the new alias map to stats configuration with serde and default support.
crates/atuin-history/src/stats.rs	Adds alias resolution to stats computation and pipeline segment handling.

_{Reviews (2): Last reviewed commit: "fix: piped aliases, and count full comma..." | Re-trigger Greptile}

[erics118]

@greptileai

[erics118]

nix fails due to an old version of nixpkgs not using a custom UA to prevent ratelimiting from crates.io. running nix flake update nixpkgs fixes the issue.