Summary

Use account-scoped hot reload for config changes under:

• channels.<channel>.accounts.<accountId>.*

instead of always restarting the entire channel.

What changed

• added account-scoped restart planning to GatewayReloadPlan
• detect account-scoped channel config paths in buildGatewayReloadPlan
• route those changes through:
  • stopChannel(channelId, accountId)
  • startChannel(channelId, accountId)
• preserve full channel restart behavior for:
  • channel-global config changes
  • mixed changes where full-channel restart takes precedence

Why

The gateway reload framework already has account-scoped channel lifecycle support, but hot reload planning previously collapsed all matching channel config changes into full channel restarts.

That makes account-only config edits broader and more disruptive than necessary.

Tests

Added coverage for:

• account-scoped channel account config -> account-only restart
• channel-global config -> full channel restart
• mixed account-scoped + channel-global changes -> full channel restart wins
• multiple account-scoped changes in one channel -> collect all impacted accounts

Validated with:

corepack pnpm exec vitest run src/gateway/config-reload.test.ts src/gateway/server.reload.test.ts

Scope / non-goals

This change is intentionally narrow.

It does not redesign active reply draining, typing lifecycle coordination, or provider-specific recovery behavior.

Closes openclaw#43935