Enh/maintenance and bugfix

[rdmrocha]

• Added ISO support as a first-class fatxlib::iso area and removed the old xiso / iso2god compatibility entry points.
• Added xtafkit extract and xtafkit god CLI subcommands, plus the matching TUI flow.
• Introduced ISO trim modes: none, preserve-layout, and compact, with compact as the default for GoD conversion.
• Made GoD conversion stream-oriented and split it into source prep, shared core, host sink, FATX sink, and compact-XDVDFS planning.
• Centralized ISO manifest and $SystemUpdate filtering so extract and compact share the same file enumeration and policy.
• Updated docs and release metadata for the new ISO workflow and bumped the release to 1.2.0.
• Fixed the trimmed GoD sizing bug so the last part no longer reads past the computed boundary.
• Fixed TUI robustness issues: panic cleanup, worker disconnect handling, flush error propagation, and delete-confirmation target capture.
• Fixed scan --deep raw-device sizing, removed the public force_stats_counts_for_test helper, tightened the OG catalog floor check, clarified the FATX threshold comment, and removed weak/redundant tests.
• Cleaned up build.rs, added direct GoD hash-chain coverage, centralized cluster-allocation helpers, and removed the Clippy suppressions by replacing them with real fixes.