docs(types) Document or use RepoPinDict/RepoOptionsDict/RepoEntryDict TypedDicts

[tony]

`RepoPinDict`, `RepoOptionsDict`, `RepoEntryDict` in `types.py:88-188` are defined but never imported or used in runtime code.

Other TypedDicts in the same file (e.g. `ConfigDict`) ARE actively used.

Options:

• (a) Use them in function signatures for type safety
• (b) Add docstring noting they are schema documentation for external tooling

Found by multi-model code review (Claude, 1/3 consensus). Finding #8.