[pranavvadd]

Summary

Adds docs/parameters_needed.md, which lists every current CarConfig value with its unit,
owner team (Software/Electrical/Mechanical), source status, and a short note on how it affects
simulation output. Unknown or guessed values are marked.

This work was done by Alex Yung in #81 and merged into the 49 branch. It never reached main,
so this PR brings it in. No code changes.

Checked

• Lists all 10 CarConfig fields (mass, battery_capacity, solar_panel_area,
  solar_panel_efficiency, electrical_efficiency, C_dA, tire_pressure,
  regen_efficiency, rho, g).
• Also lists the ignored keys in car_params.json (wheels, battery_voltage, v_starting).
• Merges cleanly into current main.

Related Issue

Closes #49

Notes

• Merging this unblocks Define Rich Parameter File Schema #50 (schema), which already includes this file, and the rest of the
  parameter chain (Create Rivanna 3S Parameter File #51, Add Parameter Loader For Rich File #52, Add Parameter Schema Validation #53) that Add Conservative/Base/Optimistic Parameter Scenarios #55 was waiting on.
• The doc flags a possible bug at physics.py:21 (electrical_efficiency multiplies instead of
  dividing). That is tracked separately in power_drained() formula / mu instead of * mu #26.