fix: ignore hidden and build directories in unicode lint test

[SuperCoolPencil]

Fixes #557

This PR updates the TestNoRawUnicodeInStringLiterals lint rule to explicitly ignore directories starting with . or _. This prevents the test from incorrectly scanning third-party dependencies downloaded by packaging tools (like Void Linux's xbps-src which creates _build-surge-xbps) during package builds.

Greptile Summary

Updates the unicode string-literal lint walk to skip hidden and underscore-prefixed directories while still scanning the module root.

• Removes hard-coded .git from skipDirs in favor of a general . / _ name prefix skip for non-root directories.
• Explicitly does not skip the walk root so packaging workdirs like _build-surge-xbps that hold go.mod still have their tree scanned.

Confidence Score: 5/5

The PR appears safe to merge; the walk-root skip issue is fixed and no blocking failure remains.

The walk root is returned without SkipDir before prefix checks, so module roots named like _build-surge-xbps are still traversed and production .go files are linted as intended.

Files Needing Attention: No files need further attention.

T-Rex Logs

What T-Rex did

• Ran a general contract validation to compare the behavior of ordinary-descendant/raw_unicode_fixture.go before and after changes.
• Confirmed that the before state produced the expected raw-Unicode violation.
• Confirmed that the after state with fixtures beneath dot- and underscore-prefixed descendants produced no violations.
• Used a reusable fixture and the executed harness to ensure traceability of the validation.
• Collected and linked the supporting artifacts (logs and scripts) as evidence for review.

_{Ran code and verified through T-Rex}

Important Files Changed

Filename	Overview
internal/lint/unicode_lint_test.go	WalkDir now skips ./_-prefixed child dirs and vendor/testdata, but never skips the project root, addressing the prior packaging false-pass.

_{Reviews (2): Last reviewed commit: "fix: prevent accidental skipping of the ..." | Re-trigger Greptile}

[github-actions]

❌ Test Failures on macos-latest

• github.com/SurgeDM/Surge/internal/service: TestLocalDownloadService_AddWithID_UsesProvidedID