Add Yahoo Finance quote tool with chart fallback, redesign header widget
with proportional truncation and context bar, refactor footer status strip,
expand test suite to 680+ tests, and fix blocking issues (usize underflow
in header, tempdir leak in finance tests, per-call HTTP client creation).
- Move src/* into crates/tui/src/ to create a proper workspace structure
- Add .claude/ and .trimtab/ directories for Trimtab closed-loop workflow
- Add DEPENDENCY_GRAPH.md and update documentation
- Update Cargo.toml files to reflect new crate dependencies
- Update CI workflows and npm package scripts
- All tests pass, release build works