Show commit signature state in commit and patch views

[romek-codes]

Add support for surfacing commit signature state in the commits list and patch view.

When gui.showCommitSignature is enabled, Lazygit now shows a signed/unsigned indicator in the commits list and a Verified subtitle in patch views for signed commits. Signed states are intentionally collapsed into a single verified presentation, while unsigned commits remain distinct.

Implementation details:

• extend commit loading to capture git signature status from git log
• add presentation helpers for commit list indicators and patch subtitles
• gate the feature behind a new gui.showCommitSignature config flag, defaulting to false
• include focused tests covering config/defaults and rendering behaviour
• update config documentation and generated config/schema outputs for the new option
• route the new subtitle text through i18n

Related discussion: #1512

This implements the signed-commit indicator requested in that discussion, with signed states collapsed into a single verified presentation and unsigned commits shown distinctly.

Please check if the PR fulfills these requirements

• Cheatsheets are up-to-date (run go generate ./...)
• Code has been formatted (see here)
• Tests have been added/updated (see here for the integration test guide)
• Text is internationalised (see here)
• If a new UserConfig entry was added, make sure it can be hot-reloaded (see here)
• Docs have been updated if necessary
• You've read through your own file changes for silly mistakes etc

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
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🟢 Metrics 0 complexity · 13 duplication

Metric	Results
Complexity	0
Duplication	13

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