Tag Length Limit + Paste

### Expected
Pasting a Tag longer than 256 characters is expected to be disregarded.

### Observed
Simplenote accepts Paste OPs of Tag Names, longer than 256 characters.

### Reproduced
1. Copy a super long string: `a1b1c1d1e1f1g1h1i1j1k1l1m1n1o1p1q1r1s1t1u1v1w1x1y1z1a2b2c2d2e2f2g2h2i2j2k2l2m2n2o2p2q2r2s2t2u2v2w2x2y2z2a3b3c3d3e3f3g3h3i3j3k3l3m3n3o3p3q3r3s3t3u3v3w3x3y3z3a4b4c4d4e4f4g4h4i4j4k4l4m4n4o4p4q4r4s4t4u4v4w4x4y4z4a5b5c5d5e5f5g5h5i5j5k5l5m5n5o5p5q5r5s5t5u5v5w5x5y5z5a6b6c6d6e6f6g6h6i6j6k6l6m6n6o6p6q6r6s6t6u6v6w6x6y6z6`.
2. Launch Simplenote
3. Click over the Tags editor (bottom area)
4. Paste

As a result, the paste OP will be accepted.

Start by reproducing the paste in Simplenote's Tags editor, described as the bottom-area editor in the issue, and trace where pasted tag names are handled. Done means a pasted tag longer than 256 characters is disregarded while shorter tag names continue to work.

Written by the indexing model from the issue text.