[Issacboy123]

Summary

This PR explains what users can expect from subagents in saved sessions. It covers what returns after reopening a parent, why unfinished children become interrupted, how explicit wake works, and when subagents remain temporary. It also records persistent subagent sessions in the coding-agent changelog.

This PR is stacked on feat/reconcile-persistent-subagents, which completes the documented persistence, restoration, and context-reconciliation behavior.

Reasoning

The sessions guide is the existing user-facing source for resume, navigation, and deletion behavior, so it is the appropriate place to explain persistence without introducing a separate conceptual surface. The documentation focuses on observable guarantees and avoids presenting internal storage mechanics as public configuration.

Changes

• Added the /subagents command to the saved-session command reference.
• Documented terminal and interrupted restoration without automatic work, task replay, or result redelivery.
• Documented explicit wake behavior for usable and isolated histories and complete captured-configuration fallback semantics.
• Clarified branch reconciliation, ephemeral parent modes, and the non-destructive effect of disabling subagent tools.
• Added an Unreleased coding-agent changelog entry for durable subagent sessions.

Testing

• node ../../node_modules/vitest/dist/cli.js --run test/suite/subagent-persistence.test.ts test/suite/subagent-services.test.ts test/suite/subagent-registration.test.ts test/suite/agent-session-harness-version.test.ts test/session-manager/fork-branch.test.ts test/session-selector-path-delete.test.ts
• npm run check

[Pepps233]

d56fc6f removes changes made to CHANGELOG.md.

Do not modify CHANGELOG.md, it will automatically be updated once we create a new github release