fix(runtime): duplicate messages, share singleton state across bundled chunks (#43683)

* Tests: add fresh module import helper

* Process: share command queue runtime state

* Agents: share embedded run runtime state

* Reply: share followup queue runtime state

* Reply: share followup drain callback state

* Reply: share queued message dedupe state

* Reply: share inbound dedupe state

* Tests: cover shared command queue runtime state

* Tests: cover shared embedded run runtime state

* Tests: cover shared followup queue runtime state

* Tests: cover shared inbound dedupe state

* Tests: cover shared Slack thread participation state

* Slack: share sent thread participation state

* Tests: document fresh import helper

* Telegram: share draft stream runtime state

* Tests: cover shared Telegram draft stream state

* Telegram: share sent message cache state

* Tests: cover shared Telegram sent message cache

* Telegram: share thread binding runtime state

* Tests: cover shared Telegram thread binding state

* Tests: avoid duplicate shared queue reset

* refactor(runtime): centralize global singleton access

* refactor(runtime): preserve undefined global singleton values

* test(runtime): cover undefined global singleton values

---------

Co-authored-by: Nimrod Gutman <nimrod.gutman@gmail.com>

test/helpers/import-fresh.ts

@@ -0,0 +1,8 @@
+export async function importFreshModule<TModule>(
+  from: string,
+  specifier: string,
+): Promise<TModule> {
+  // Vitest keys module instances by the full URL string, including the query
+  // suffix. These tests rely on that behavior to emulate code-split chunks.
+  return (await import(/* @vite-ignore */ new URL(specifier, from).href)) as TModule;
+}