kurarin: url encoding may ignore the last cell

[semiexp]

For 5x6 problems, the dot on the most bottom-right cell is ignored.

pzprjs/src/variety/kurarin.js

Line 357 in 92d5cb0

this.genericDecodeNumber16((bd.dots.length >> 1) | 1, function(idx, val) {

pzprjs/src/variety/kurarin.js

Line 369 in 92d5cb0

this.genericEncodeNumber16((bd.dots.length >> 1) | 1, function(idx) {

I think (bd.dots.length >> 1) | 1 should be (bd.dots.length + 1) >> 1 in these lines.

• For 5x6 problems, there are 9*11 = 99 dots
• We need 50 (= ceil(99/2)) values to encode all the dots
• (bd.dots.length >> 1) | 1 = 49 | 1 = 49, which is one less than needed

[semiexp]

I saw this problem in https://pzprxs.vercel.app/p?kurarin but I think the problem also occurs in the code in this repo