Response-Based Gravity in a Structured Spacetime Lattice v2.1

This work presents a response-based framework for interpreting gravity as a material response of a structured spacetime lattice. The study proposes that galactic rotation curves can be interpreted as measurements of spacetime properties, allowing extraction of effective parameters such as the critical acceleration (a0), transition sharpness (k), and response amplitude (epsilon). This work is released as a conceptual and exploratory theory statement. It does not claim completeness, final validation, or consensus with existing models. The author is an independent researcher, and this work is shared for open reference only. Readers are encouraged to interpret the content independently. No direct discussion, feedback, or correspondence is expected. Data referenced in this work are obtained from publicly available sources (e.g., SPARC database). No new observational data are provided. This release is intended as a standalone theoretical proposal.