store: count body decodes at the decode site, bound the proposal parent memo, and probe spentness on the connected create

changelog.d/proposal-parent-followup.md

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+Changed
+
+- **Packed body decodes are counted at the decode site.** The counter the
+  mempool and block-proposal pins read sits on the tx table's outs decoder, so
+  every per-fk decode is seen; the confirm write stage's full decoder is not
+  counted.
+- **Txid and spender resolution no longer decode the body.** Resolving a txid
+  to its row, probing whether an output is spent, and recording a spend read
+  the `txid.body` identity only; the packed decode runs only for a reader that
+  needs the record.
+- **A block proposal keeps only the parent outputs it spends.** The check
+  resolves each confirmed parent on the connected chain, decodes it once, and
+  holds only the spent outputs until it returns; a row that exists only in a
+  reorged-out block is not an input.

changelog.d/proposal-spentness-connected.md

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+Fixed
+
+- **Spentness is probed on the connected create.** `gettxout`, mempool accept,
+  the proposal check, and the Electrum and Esplora spent checks read the
+  spender slots of the row on the best chain; a newer never-connected row for
+  the same txid no longer hides a confirmed spend.