Migrate Windows file clients to the broker

[Weidong Cui (wdcui)]

This PR migrates Windows file, registry, PE loader, NLS, section, and runner operations to broker-backed LiteBox file APIs, stores registry keys and typed values under the reserved /registry namespace, requires broker-provided filesystem contents, and adds shared in-process broker coverage for the migrated behavior.

[github-actions]

🤖 SemverChecks 🤖 ⚠️ Potential breaking API changes detected ⚠️

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--- failure constructible_struct_adds_field: struct exhaustively constructible through public API adds field ---

Description:
A pub struct that could be exhaustively constructed with a literal using only public API has a new pub field, breaking existing exhaustive literals.
        ref: https://doc.rust-lang.org/reference/expressions/struct-expr.html
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/constructible_struct_adds_field.ron

Failed in:
  field CliArgs.broker_control_channel in /home/runner/work/litebox/litebox/litebox_runner_windows_on_linux_userland/src/lib.rs:44
  field CliArgs.broker_proxy_url in /home/runner/work/litebox/litebox/litebox_runner_windows_on_linux_userland/src/lib.rs:53

--- failure struct_pub_field_missing: pub struct's pub field removed or renamed ---

Description:
A publicly-visible struct has at least one public field that is no longer available under its prior name. It may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/struct_pub_field_missing.ron

Failed in:
  field initial_files of struct CliArgs, previously in file /home/runner/work/litebox/litebox/target/semver-checks/git-ulitebox/42a6dbcf3605a4ec8fb3f188530db4e288ce6c97/litebox_runner_windows_on_linux_userland/src/lib.rs:37

--- failure inherent_method_missing: pub method removed or renamed ---

Description:
A publicly-visible method or associated fn is no longer available under its prior name. It may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/inherent_method_missing.ron

Failed in:
  WindowsShimBuilder::new, previously in file /home/runner/work/litebox/litebox/target/semver-checks/git-ulitebox/42a6dbcf3605a4ec8fb3f188530db4e288ce6c97/litebox_shim_windows/src/lib.rs:409
  WindowsShimBuilder::default_fs, previously in file /home/runner/work/litebox/litebox/target/semver-checks/git-ulitebox/42a6dbcf3605a4ec8fb3f188530db4e288ce6c97/litebox_shim_windows/src/lib.rs:426

--- failure method_parameter_count_changed: pub method parameter count changed ---

Description:
A publicly-visible method now takes a different number of parameters, not counting the receiver (self) parameter.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#fn-change-arity
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/method_parameter_count_changed.ron

Failed in:
  litebox_shim_windows::WindowsShim::load_program takes 4 parameters in /home/runner/work/litebox/litebox/target/semver-checks/git-ulitebox/42a6dbcf3605a4ec8fb3f188530db4e288ce6c97/litebox_shim_windows/src/lib.rs:510, but now takes 3 parameters in /home/runner/work/litebox/litebox/litebox_shim_windows/src/lib.rs:492