docs: reconcile hib_changes onto flat structure
Bring over comprehensive documentation, CLI tools, and project
scaffolding from the archived v2/ branch onto the rebuilt flat
main. All v2/ path references updated to match flat layout.
- docs/: architecture, decisions, phases, progress, findings, etc.
- docker/tempo: telemetry stack (Grafana + Tempo)
- CLAUDE.md, .claude/CLAUDE.md: comprehensive project guides
- CHANGELOG.md, TODO.md, README.md: project meta
- consult, ctx: CLI tools
- .gitignore: merged entries from both branches
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