[karim-alweheshy]

Summary

• Track resource-bundle files and owners needed by native Xcode Previews.
• Materialize and stage the selected Preview's owned resources across Bazel
  output locations, preserving bundle-relative paths for app- and
  library-owned Previews.
• Make migrations ownership-aware: reject conflicting or unowned destinations
  and recover interrupted moves without deleting resources owned elsewhere.

Based on branch preview-stack-native-previews-v2. This adds resource-bundle
support to its resource-free native Preview opt-in without changing ordinary
Bazel-owned configurations.

Review order

1. Resource discovery/materialization and dual-aspect tests: retain exact
   producers, nested paths, asset catalogs and localization inputs.
2. Provider propagation, br output groups and generated bundle-path settings:
   check the contract for app, library and mixed-language targets.
3. Copy/staging ownership and migration tests: check that conflicting producers
   and destinations fail without overwriting unowned files.

Validation

This resegmented branch has exactly the same Git tree as the previously
CLI-validated candidate. Root tests and lint are rerun at this head. The example
CLI/build/staging evidence below is reused from that identical tree, not claimed
as a new execution during this split.

• All 140 root Bazel 9 test targets plus the generated-docs test pass at the
  proposed head on macOS with Xcode 27.0. Repository Buildifier passes.
• Resource regressions cover dual-aspect discovery, generated and localized
  inputs, asset catalogs, output-group ownership, conflicts and interrupted
  migrations. Changed copy/staging shell scripts pass ShellCheck.
• The checked-in example generates with rules_swift 3.5 and rules_apple 4.4.
  Previews-configuration CLI builds pass for library, framework, explicit-module,
  macOS app and generic iOS Simulator schemes with signing disabled.
• The staged message matches its source in the macOS app resource directory,
  iOS app bundle, and library-product sibling bundle; each bundle plist validates.

These are build/staging checks. Fresh Canvas rendering, runtime resource lookup
and signed-runtime verification remain pending for this extracted stack.

Testing

• Run the focused resource-bundle and migration tests, including conflict,
  ownership, and interrupted-migration cases.
• Generate and build the example with a resource bundle used by an app-owned
  Preview and a library-owned Preview; verify staged bundle contents and runtime
  lookup at the intended bundle location.
• When Canvas validation is available, request each affected Preview and confirm
  the expected view renders and loads its resource. A successful build or
  staged-file check alone does not establish Canvas rendering.