feat(act): configurable correlation id generator (ACT-404)

[Rotorsoft]

Summary

Closes #725.

Replaces randomUUID() for correlation ids with a configurable delegate plus a readable, time-monotonic default of the form {state[:4]}-{action[:4]}-{4 ms}{4 random} (18 chars, lowercase base36).

// default
await app.do("incrementBy", { stream: "counter-1", actor }, { by: 1 });
// → event.meta.correlation === "coun-incr-lwxk9p3a"

// custom (tenant-prefixed)
const correlator: Correlator = ({ state, action, actor }) =>
  \`${actor.tenantId}-${state.slice(0,4)}-${action.slice(0,4)}-${Date.now().toString(36)}\`;
act().withState(...).build({ correlator });

Why

• Index locality — random UUIDs scatter across the correlation index causing page splits and bloat. The time-ordered prefix in the default groups contemporaneous inserts on the same B-tree pages.
• Readability — `coun-incr-…` tells operators what the workflow is at a glance; `f47ac10b-58cc-…` doesn't.
• No coordination required — 4-char random tail (1.68M values per ms) keeps competing-consumer workers collision-safe without DB sequence round-trips.

What changed

• New `Correlator` type and `CorrelatorContext` exported from `@rotorsoft/act`
• New `ActOptions.correlator?: Correlator` — defaults to the readable shape
• `event-sourcing.action()` takes the correlator (default-fall-through for direct callers in tests)
• `buildEs` binds the correlator into `EsOps.action` so the orchestrator's call sites stay unchanged
• `runCloseCycle` accepts a pre-computed `correlation` (Act passes one minted via the configured correlator with a synthetic `$close` context, so close tombstones share the user's id scheme)
• Reactions still propagate `reactingTo.meta.correlation` — the chain is untouched
• Wolfdesk bootstrap demonstrates a tenant-prefixed correlator

Test plan

• 10 new tests in `libs/act/test/correlator.spec.ts` cover: default format width, prefix truncation, lowercase invariant, 1000-iteration uniqueness, timestamp progression, delegate override, reaction chain propagation, context shape, and close-cycle integration
• Full `@rotorsoft/act` suite passes (555 tests, no regressions)
• Broader suite passes — `libs/act-sqlite`, `libs/act-tck`, `libs/act-pino` (1110+ tests total)
• Wolfdesk tests pass with the custom correlator wired
• Typecheck clean
• Biome lint clean
• `correlator.ts` at 100% coverage

Docs

• `docs/docs/concepts/event-sourcing.md` — new "Correlation IDs" section with default format, common alternative shapes (tenant prefix, trace-id propagation, idempotency-key bridge, DB-issued monotonic, ULID/UUIDv7), and the close-cycle convention
• Memory: `project_book_correlator.md` book notes covering why UUIDs hurt indexes, the readable default, and six common delegate patterns

🤖 Generated with Claude Code

[github-actions]

🎉 This PR is included in version @rotorsoft/act-v0.42.0 🎉

The release is available on:

• @rotorsoft/act-v0.42.0
• GitHub release

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