* refactor: make OutboundSendDeps dynamic with channel-ID keys
Replace hardcoded per-channel send fields (sendTelegram, sendDiscord,
etc.) with a dynamic index-signature type keyed by channel ID. This
unblocks moving channel implementations to extensions without breaking
the outbound dispatch contract.
- OutboundSendDeps and CliDeps are now { [channelId: string]: unknown }
- Each outbound adapter resolves its send fn via bracket access with cast
- Lazy-loading preserved via createLazySender with module cache
- Delete 6 deps-send-*.runtime.ts one-liner re-export files
- Harden guardrail scan against deleted-but-tracked files
* fix: preserve outbound send-deps compatibility
* style: fix formatting issues (import order, extra bracket, trailing whitespace)
* fix: resolve type errors from dynamic OutboundSendDeps in tests and extension
* fix: remove unused OutboundSendDeps import from deliver.test-helpers
Landed from #23249 by @Sid-Qin.
Includes extra regression tests for agentId precedence + blank fallback.
Co-authored-by: Sid <201593046+Sid-Qin@users.noreply.github.com>
