Add a new SymbolTable module for interned string identifiers.
The module implements a bidirectional mapping between strings and
Symbol IDs using a HashMap. Key functionality includes:
- intern(): Add a string to the table and return its Symbol ID
- get(): Look up a string by Symbol ID
- resolve(): Get the original string for a Symbol ID
- intern_pair() and intern_coords(): Helper functions for structured
data interning
The implementation includes unit tests to verify correct behavior.
Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/Qwen3.5-35B-A3B-GGUF:Q5_K_M)
The CSV export used Box<dyn Iterator<Item = Option<usize>>> to unify
empty and non-empty row iteration, violating the CLAUDE.md rule that
Box/Rc container management should be split from logic. Replaced with a
direct for loop over row indices, removing both the Box and the Option
sentinels used to represent "placeholder empty row/col".
Also removes unused pub use cell::CellKey re-export and an unused
import in cell.rs tests.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Removes dead use statements across dispatch, formula, import, model, and
UI modules. Prefixes intentionally unused variables with _ in app.rs,
analyzer.rs, and grid.rs.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
