Add Scopely-native navigation shortcut actions

[Guffawaffle]

Summary

Add native_shortcut_galaxy and native_shortcut_events bindings that invoke Scopely's own navigation callbacks. The existing show_galaxy and show_events actions continue to navigate directly to their configured sections.

Defaults are CTRL-G and CTRL-E. These bindings operate in mod-hotkey mode; Scopely-hotkey mode uses Scopely's bindings. F5 remains the default for zoom_preset5. The legacy show_galaxy_native name remains an alias.

Mod keyboard camera actions now honor hotkeys_enabled and use_scopely_hotkeys. Automatic default zoom and native mouse behavior remain active.

Validation and review

• Reviewed head: 156de8f
• Base/merge: a4b8ca9
• Diff hash: 27cf47111ae7c2e65360436afbe1aa17c9ce3b5f
• Receipt: 1309ea1e3db34aff444e943f63f03b931fb1231b22d8e426750a01182cef5b02
• General, hostile, and independent reviews found no confirmed source defect.
• Windows release mods build and git diff --check passed; all platform and example-config CI checks passed.
• Current Windows native code confirms both callbacks enforce CanUseShortcuts and do not read CallbackContext. Its pointer-plus-int layout matches the supplied 16-byte storage; runtime_invoke handles the managed invocation ABI.
• Previous Windows manual testing confirmed native Galaxy and Events behavior. Events was tested with an explicitly configured F5 binding; F5 is not this PR's shipped Events default.
• Static integration with Arbitrate modified directional hotkeys #266 is conflict-free. Its frame-scoped input-cache correction addresses an existing shared-cache dependency.

Remaining evidence

• record the deployed artifact hash and exercise both actions in eligible and ineligible UI states on macOS
• exercise camera shortcuts with mod hotkeys enabled, disabled, and Scopely mode selected, including presets and native mouse-wheel behavior
• future client signature changes remain a risk for the fixed callback-context layout and name-plus-arity lookup

Dependencies

This PR is independent of #253. The observer-only #255 no longer depends on either PR. #268 consumes #255 and excludes native shortcut work.

[Guffawaffle]

Review refresh complete at 156de8f, receipt 1309ea1e3db34aff444e943f63f03b931fb1231b22d8e426750a01182cef5b02. All three lanes found no confirmed source defect; the Windows release mods build and all CI checks pass.

Native-code inspection confirms both callbacks retain CanUseShortcuts and ignore the zero callback context. Static integration with #266 is conflict-free. The PR description now reflects the observer/consumer split, clarifies that the earlier F5 test used a custom binding, and records the remaining macOS and camera-mode runtime coverage.