[TheGreatAxios]

Summary

• Trims comments across apps/hub/src, apps/sidecar/src (including the full workflow-host-wiring.ts), and 22 tools/* source files so each block explains why, not what.
• Blocks whose rationale needed more than 1-3 lines were moved to docs/, with a one-line link left in code: docs/sidecar-tool-package-durability.md and docs/sidecar-conversation-durability.md (both new).
• No behavior, names, or types changed; unrelated lines untouched.
• Rebased onto latest main: dropped commits that only touched now-deleted tools/{github,gotenberg,reddit,granola,linear} packages, and git rm'd files deleted upstream on every modify/delete conflict.
• Removed a stale INTR-310 reference.

Test plan

• find-blocks scanner confirms zero remaining 8+-line comment blocks in every file this PR touches
• bun run check green after a full bun install refresh (typecheck, lint, fmt, full test suite)

[linear-code]

CL-8377