Refactor SFTP helpers into a dedicated part file

[GT-610]

Summary

• Moved SFTP path, decompression, time formatting, and sort helpers out of sftp.dart into sftp_helpers.dart
• Removed the unused Range model file
• Kept SFTP page behavior unchanged while improving code organization

Testing

• Not run (not requested)

Summary by CodeRabbit

• Refactor
  • Reorganized SFTP storage helpers into a dedicated module for cleaner code structure.
• Chores
  • Removed an unused internal Range utility class.
• New Features
  • Added a shell-safe single-quote escaping utility for building shell arguments.
• Tests
  • Added tests verifying single-quote escaping and behavior with special characters.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: d0075d62-7f3c-43e2-91cf-230caa52357e

📥 Commits

Reviewing files that changed from the base of the PR and between 075c1b0 and 68027c4.

📒 Files selected for processing (4)

• lib/core/utils/shell_quote.dart
• lib/view/page/storage/sftp.dart
• lib/view/page/storage/sftp_helpers.dart
• test/sftp_helpers_test.dart

✅ Files skipped from review due to trivial changes (2)

• lib/core/utils/shell_quote.dart
• test/sftp_helpers_test.dart

🚧 Files skipped from review as they are similar to previous changes (2)

• lib/view/page/storage/sftp.dart
• lib/view/page/storage/sftp_helpers.dart

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📝 Walkthrough

Walkthrough

This PR removes the public Range<T extends num> class from lib/data/model/app/range.dart. It refactors SFTP helper logic by adding part 'sftp_helpers.dart'; to lib/view/page/storage/sftp.dart, extracting inline helpers (path normalization, decompression-command lookup, timestamp formatting, and sorting) into the new lib/view/page/storage/sftp_helpers.dart. It also adds shellSingleQuote in lib/core/utils/shell_quote.dart and a corresponding test test/sftp_helpers_test.dart.

Possibly related PRs

• fix(sftp): Fix SFTP file download failures on Windows #993: Modifies SFTP path normalization logic that overlaps with the extracted _normalizeSftpPath helper.
• fix(storage): Fixed an issue with the SFTP path history #1077: Centralizes or uses _normalizeSftpPath and related SFTP helper behavior, directly related to this extraction.

Suggested reviewers

• lollipopkit

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main refactoring: moving SFTP helpers into a dedicated part file (sftp_helpers.dart), which is the primary structural change across the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch p3-code-quality-cleanup

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@lib/view/page/storage/sftp_helpers.dart`:
- Around line 5-9: The _getDecompressCmd function is vulnerable to shell
injection by inserting raw filename into shell commands; fix it by performing
POSIX single-quote escaping on the filename before substitution and using single
quotes around the escaped value when replacing FILE in _extCmdMap entries:
create or use a helper (e.g., escapeForSingleQuotes) that replaces each single
quote in filename with '\'' sequence, then replaceAll('FILE',
"'$escapedFilename'") in _getDecompressCmd (referencing _getDecompressCmd and
_extCmdMap) so filenames with quotes, $, backticks, etc. are safely quoted.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 7665a83a-5fdd-4f3d-80f7-8c1585c1ed0e

📥 Commits

Reviewing files that changed from the base of the PR and between 7f63316 and 075c1b0.

📒 Files selected for processing (3)

• lib/data/model/app/range.dart
• lib/view/page/storage/sftp.dart
• lib/view/page/storage/sftp_helpers.dart

💤 Files with no reviewable changes (1)

• lib/data/model/app/range.dart