016 store lifecycle inserted removed

// Ruling 5: stores emit inserted/removed/updated, and everything reactive
// compiles down into these same interceptor branches. Here the store's own
// contract maintains COUNT(*) in a second (singleton) store: `inserted`
// bumps it, `removed` decrements it. The lifecycle branches fire from the
// insert and take write paths — the qbody transplant pattern.
//
// The bodies don't read the row, so the payload is DISCARDED (`_`) — the same
// KORU100 discipline as any binding; naming a field you never use is rejected
// (690_032). Consuming the field is 690_033.
//
// Bare take (no `[entity]`) is frictionless: swap-remove, no obligation.

import std/io
import std/store

std/store:new(stats) { count: 0[i64] }

std/store:new(pool, capacity: 64) { hp: i64 }
! inserted _ |> std/store:stored { stats.count: stats.count + 1 }
! removed _ |> std/store:stored { stats.count: stats.count - 1 }

std/store:watch(stats)
! count c |> std/io:print.ln("count {{ c:d }}")

std/store:insert(pool) { hp: 1 }
| row a |> std/store:insert(pool) { hp: 2 }
    | row b |> std/store:take(pool[b])
        | item _ |> _