refactor(self-mod): drop request_rebuild — approvals now bundle rebuild+restart

install_packages and add_mcp_server already did the right thing on approve
(install auto-rebuilt+killed, add_mcp_server just killed), so request_rebuild
was redundant plumbing agents sometimes called after an install — wasting an
admin approval round-trip. Delete it end-to-end:

- container/agent-runner/src/mcp-tools/self-mod.ts: remove requestRebuild
  tool + registration; update install_packages description.
- src/modules/self-mod/{request,apply,index}.ts: drop handleRequestRebuild
  + applyRequestRebuild + registrations; rewrite the rebuild-failed notify
  to point admins at retrying install_packages instead.
- src/modules/{approvals,self-mod}/{agent,project}.md and skill/self-
  customize/SKILL.md: scrub agent-facing references; clarify that
  add_mcp_server needs no rebuild (bun runs TS directly).
- docs/{module-contract,architecture-diagram,checklist,db-central,shared-
  source,v1-vs-v2/*}.md, CLAUDE.md, pending-approvals migration comment,
  approvals/index.ts docstring, REFACTOR.md: trailing references.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/architecture-diagram.md

@@ -32,7 +32,7 @@ flowchart TB
     direction TB
     PollLoop["Poll Loop<br/>(container/agent-runner)"]
     Provider["Agent providers<br/>(claude, opencode, mock; todo: codex)"]
-    MCP["MCP Tools<br/>send_message, send_file, edit_message,<br/>add_reaction, send_card, ask_user_question,<br/>schedule_task, create_agent,<br/>install_packages, add_mcp_server, request_rebuild"]
+    MCP["MCP Tools<br/>send_message, send_file, edit_message,<br/>add_reaction, send_card, ask_user_question,<br/>schedule_task, create_agent,<br/>install_packages, add_mcp_server"]
     Skills["Container Skills<br/>(container/skills/)"]
     InDB[("inbound.db<br/>host writes<br/>even seq<br/>messages_in<br/>destinations<br/>processing_ack")]
     OutDB[("outbound.db<br/>container writes<br/>odd seq<br/>messages_out<br/>heartbeat file")]