[area:live-data] Pasting over a live-data cell is accepted and announced, then the next refresh wipes it without a word #232

Found by the PO while reviewing #231 (#207), on a production build of 6a46a2f. The same on main before it: #231 did not touch the paste path.

Repro (1280, Thai)

1. Live data → "ลองต่อ: ยอดขายสด" → Test → Save and add → Insert. A 5-row block lands at A1:G6, refreshing every 5 s.
2. Type PASTED into I2 (outside the block), copy it.
3. Select B3 (inside the block) and press Ctrl+V.

Ctrl+Z afterwards does not bring PASTED back either. The person was told the paste worked, and a few seconds later it is gone. Typing into the same cell is refused out loud since #231; pasting is the other door into the same cell and it is still open.

Related, smaller: with a range selected whose anchor is a live cell (B5:C5), typing is refused and announced, but no note appears under the cell, because the note only shows for a single-cell selection.

Done when

• A paste whose target includes live-data cells (or a template's locked structure) does not write into them, and says so the way Say why a live-data or template cell refused an edit (#207) #231 does — which cells, why, and that "เอาออก" / "Remove" is the way to edit them. Choose and write down in the PR whether the paste is refused whole (Excel's behaviour with protected cells) or applied to the free cells only; the PO's preference is refuse whole, since a partial paste shifts rows against each other.
• The paste announcement never says "pasted into B3" for a cell that did not take it.
• Ctrl+Enter / fill / cut into a live block: check each path, same rule.
• Typing on a range anchored on a live cell shows the note too (or the PR says why not).
• An e2e flow that pastes into a live block and fails on main.

Part of the hold set (no silent wrong values, no silent data loss). Queue: next after #226.