Add armonia workspace setup scripts (bootstrap + migration)

[aarontrowbridge]

Every user — Harmoniqs dev or external contributor — should get the same canonical workspace layout with one command.

Acceptance Criteria

• tools/bootstrap-armonia.sh — fresh-machine setup: creates ~/armonia/{repos/{packages,demos},data/{env,problems,runs,vaults}}, clones canonical public repos by tier (--minimal / --standard / --full), idempotent
• tools/migrate-to-armonia.sh — updated for the three-bucket repos layout (packages/, demos/, flat); still idempotent
• Both scripts safe to re-run; curl-able raw from GitHub for users who have not cloned anything yet

[aarontrowbridge]

Hygiene note 2026-08-27: Overlaps #386 (seamless migration) and #312 (vault auto-setup). #386 is the expanded, current tracker covering bootstrap + migration + retirement + path-orphan fixes. Consider closing this as superseded by #386 or keeping as slice 1 of that epic.