docs: update stale sub-agent context injection details (#79470)

Summary:
- Correct stale sub-agent docs to list the current minimal bootstrap context files.
- Add changelog credit for @lastguru-net.

Verification:
- pnpm docs:list
- pnpm exec oxfmt --check --threads=1 docs/tools/subagents.md CHANGELOG.md
- git diff --check
- GitHub CI: check-docs, Real behavior proof

CHANGELOG.md

@@ -145,6 +145,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Docs/Subagents: correct the listed sub-agent bootstrap context files to include `SOUL.md`, `IDENTITY.md`, and `USER.md`. (#79470) Thanks @lastguru-net.
 - OpenAI/Codex: install the Codex runtime plugin from npm during OpenAI onboarding and load it automatically for implicit OpenAI model routes, while preserving manual PI runtime overrides. Fixes #79358.
 - OpenAI/realtime voice: defer `response.create` while a realtime response is still active, retry after `response.done`/`response.cancelled`, and align GA input transcription/noise-reduction defaults with the Codex realtime reference so Discord/Voice Call consult results can resume speaking instead of tripping the active-response race.
 - OpenAI/realtime voice: avoid duplicate barge-in cancellation requests, log realtime model interruption/cutoff events in Discord voice logs, and treat OpenAI's no-active-response cancellation reply as a completed cancel so Discord voice sessions do not wedge pending speech after fast interruptions.

docs/tools/subagents.md

@@ -547,7 +547,7 @@ still need normal device approval for scope upgrades.
 - Sub-agent announce is **best-effort**. If the gateway restarts, pending "announce back" work is lost.
 - Sub-agents still share the same gateway process resources; treat `maxConcurrent` as a safety valve.
 - `sessions_spawn` is always non-blocking: it returns `{ status: "accepted", runId, childSessionKey }` immediately.
-- Sub-agent context only injects `AGENTS.md` + `TOOLS.md` (no `SOUL.md`, `IDENTITY.md`, `USER.md`, `HEARTBEAT.md`, or `BOOTSTRAP.md`).
+- Sub-agent context only injects `AGENTS.md`, `TOOLS.md`, `SOUL.md`, `IDENTITY.md` and `USER.md` (no `MEMORY.md`, `HEARTBEAT.md`, or `BOOTSTRAP.md`).
 - Maximum nesting depth is 5 (`maxSpawnDepth` range: 1–5). Depth 2 is recommended for most use cases.
 - `maxChildrenPerAgent` caps active children per session (default `5`, range `1–20`).