Move scanning into a guarded subprocess worker

[rsgalloway]

This pull request implements several improvements for the sview application, focusing on safer and more configurable directory scanning, improved error reporting, persistent UI state, and a refreshed dark theme. It also introduces a --debug mode for enhanced troubleshooting and updates the configuration system to support new worker safety settings.

Scanner worker improvements:

• Directory scanning now runs in a subprocess worker, enabling safer cancellation and better isolation.
• Added configurable scan worker guardrails: process priority (nice_increment), memory limit (memory_limit_mb), and timeout (timeout_seconds), all exposed in the user config file. The default memory cap is now opt-in to avoid false positives. [1] [2] [3] [4]

Configuration and state management:

• The config file (config.json) schema is extended to include scanner worker settings, and a new persistent UI state file (ui_state.json) is introduced with load/save helpers. [1] [2] [3]
• The application version is bumped to 0.1.2 across all relevant files. [1] [2]

Debugging and error reporting:

• Added a --debug command-line flag to enable detailed scanner debug output in the terminal, documented in the README.md. [1] [2] [3] [4]

UI and model enhancements:

• The dark theme is refreshed with improved color palette and widget styling for better visual clarity.
• BrowserItem now supports serialization/deserialization via to_dict and from_dict methods, and sequence metadata can be updated in-place. [1] [2]

Documentation:

• The README.md and CHANGELOG.md are updated to reflect these changes, including new configuration options and usage instructions. [1] [2] [3]

Let me know if you have questions about any of these updates!

[Copilot]

Pull request overview

This PR refactors sview directory scanning to run in an isolated subprocess worker (with configurable guardrails), expands config/state persistence, and refreshes parts of the UI (including a new icon view and updated dark theme), while bumping the app version to 0.1.2.

Changes:

• Run directory scans via a QProcess-launched python -m sview.worker and deserialize results back into the UI.
• Extend config/state: add scan-worker safety settings in config.json and persist lightweight UI state in ui_state.json.
• UI updates: add icon-based center pane, new inspector actions for sequence metadata, and dark-theme tweaks.

Reviewed changes

Copilot reviewed 15 out of 16 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
tests/test_scanner.py	Updates sequence expectations and adds ScanResult serialization round-trip coverage.
sview/worker.py	New subprocess entrypoint to run scans and emit JSON (stdout) + progress/errors (stderr).
sview/scanner.py	Adds ScanResult (de)serialization and adjusts sequence grouping/metadata behavior.
sview/qt/table.py	Makes columns interactive with fixed defaults; adds item update helper; formats mtime for 0/unknown.
sview/qt/main_window.py	Moves scanning to QProcess, adds debug/error dialogs, introduces icon view + UI state persistence.
sview/qt/inspector.py	Adds “Find Missing” and “Get Size” actions and handles unknown timestamps.
sview/qt/icon_view.py	Adds new icon/card-based contents view with secondary metadata text.
sview/qt/app.py	Adds --debug flag wiring and updates argument parsing for initial path.
sview/model.py	Adds BrowserItem (de)serialization support.
sview/controller.py	Adds in-place sequence metadata update helper.
sview/config.py	Adds scan-worker config + UI state load/save helpers; adjusts config save behavior.
sview/init.py	Bumps version to 0.1.2.
sview.png	Updates screenshot asset.
README.md	Documents --debug, ui_state.json, and scan-worker settings.
pyproject.toml	Bumps project version to 0.1.2.
CHANGELOG.md	Adds 0.1.2 release notes.

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