Rename Engineer in Box to Shiny (gt-8tmz.10)

Renamed mol-engineer-in-box to mol-shiny across all documentation
and test code. This is a Mad Max reference - the canonical 'right
way to engineer'.

Files updated:
- docs/architecture.md (15 references)
- docs/molecules.md (7 references)
- docs/bootstrap.md (1 reference)
- docs/molecular-chemistry.md (1 reference)
- docs/polecat-wisp-architecture.md (1 reference)
- internal/beads/molecule_test.go (test function rename)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/polecat-wisp-architecture.md

@@ -56,7 +56,7 @@ and cleanup within a single ephemeral container.
 │  │  Storage: .beads/ (git-tracked)                                │  │
 │  │                                                                 │  │
 │  │  Could be:                                                      │  │
-│  │  - mol-engineer-in-box (full workflow)                         │  │
+│  │  - mol-shiny (full workflow)                                   │  │
 │  │  - mol-quick-fix (fast path)                                   │  │
 │  │  - Any custom work molecule                                    │  │
 │  │  - Direct issue (no molecule, just task)                       │  │