refactor(wearlib): add typed connectivity and protocol APIs

[Foxpace]

Adds typed, testable APIs for communication between the phone and Wear OS applications.

What was added

• Connection repository, connection state, use cases, node selection, and Hilt bindings.
• File-transfer client, metadata model, path codec, and Google Play Services implementation.
• Typed wearable commands, command codec, and sensor catalog storage.
• Codec and node-selection tests plus reusable fake fixtures.

How it works

Application code talks to small repository and client interfaces. Google Play Services implementations discover the correct node and transport messages or files, while codecs translate typed commands and safe file paths to their wire representation. Fakes allow the same flows to run in unit and emulator tests.

Stack position

Layer 3 of 31 in the SensorBox refactor stack. Review this PR against its configured base to see only this layer.

Validation

• Full stack: ./gradlew test — BUILD SUCCESSFUL (160 tasks)

[Foxpace]

Superseded by #46, which targets master and shows the final current tree. Closing this stacked layer so review stays on the consolidated diff; this PR remains available as history.

[Foxpace]

Stack restored at the author's request. This PR is again part of the original 31-layer refactor chain. The architecture work continues as stacked PRs #47 through #54; consolidated PR #46 is superseded.