Add unified community Tool Center

[TrapEmAll]

Summary

• replace the two-preset External Tools page with a catalog-backed Tool Center
• add reviewed native workflows for extract-xiso, Xenia, Xenia Canary, and the existing XeXTool integration
• add discovery and managed launching for user-supplied Velocity, Iso2God, God2ISO, Xbox Image Browser, and Le Fluffie
• add persistent executable paths, SHA-256 identification, platform-aware availability, project credits, source links, and CLI parity
• intentionally exclude FATXplorer and J-Runner

Safety and compatibility

• commands are executed as argument vectors with shell=False
• reviewed GUI presets are locked; custom vectors are treated as potentially modifying
• extract-xiso rewrite and all CLI argument overrides require explicit modification confirmation
• no new third-party binaries are bundled or downloaded
• legacy GUI tools are launch-managed without invented command-line arguments
• XboxUnity remains HTTP-only; this change does not alter its transport behavior

Licensing and provenance

The Tool Center documentation and third-party notices distinguish bundled XeXTool from user-supplied integrations and link to known upstream projects. Legacy tools without a clearly canonical, redistributable source are not bundled.

Validation

• python -m ruff check .
• python -m compileall -q .
• python tests.py (114/114)
• python main.py --list-tools in portable mode
• successful PyInstaller Windows executable build

Follow-up

Future adapters can extend the declarative catalog without adding one-off GUI branches. Managed downloading should only be considered per tool after release provenance, checksums, and redistribution terms are independently established.