## Summary
- Creates `docs/concepts/node-infrastructure.md` with full migration of
two Learn Hub articles: IC-OS overview (SetupOS, HostOS, GuestOS) and
Trusted Execution Environments
- TEE section covers: SEV-SNP memory encryption, VM launch measurements,
attestation reports (including node-to-node and external attestation
paths), sealing keys, disk partition layout table (A/B sets, which
partitions are encrypted and why), traditional-vs-sealing-key encryption
history, HKDF/LUKS key derivation, full 7-step GuestOS upgrade process
with Upgrade VM and mutual attestation, and full emergency recovery
section (manual rollback with NNS proposal steps + Recovery-GuestOS
mechanism with upgrade-vs-recovery comparison table)
- Adds 3 images from Learn Hub: TEE architecture overview
(`tee-overview.jpg`), SEV-SNP attestation report diagram
(`tee-attestation-report.svg`), SEV-SNP key derivation diagram
(`tee-key-derivation.svg`)
- Adds `concepts/node-infrastructure` to the explicit Concepts sidebar
after `app-architecture`
- Updates `docs/concepts/https-outcalls.md`: replaces the Learn Hub TEE
link with the new internal path; removes a stale Learn Hub
further-reading link for the skipped HTTPS Outcalls article

## Staging files deleted
-
`.migration/learn-hub/how-does-icp-work/node-infrastructure/overview.md`
→ `docs/concepts/node-infrastructure.md`
-
`.migration/learn-hub/how-does-icp-work/node-infrastructure/trusted-execution-environments.md`
→ `docs/concepts/node-infrastructure.md#trusted-execution-environments`

## Sync recommendation
hand-written

<!-- Upstream: informed by Learn Hub articles "Overview" (Node
Infrastructure), "Trusted Execution Environments" (migrated, source
retired) -->

…ocs (#208)

## Summary

Migrates all 57 developer-relevant articles from the Learn Hub \"How
does ICP work?\" section into the developer docs, replacing Learn Hub as
the canonical source for ICP protocol concepts before the site is
retired.

This was executed as 9 content batch PRs plus a post-migration review
pass, all merged into this staging branch before landing on `main`:

**Batch 1 — Protocol stack** (#209): Consensus, peer-to-peer, message
routing, execution layer, state synchronization, and performance concept
pages under `docs/concepts/protocol/`.

**Batch 2 — Node infrastructure** (#210):
`docs/concepts/node-infrastructure.md` — TEE (SEV-SNP) attestation,
IC-OS layer model (SetupOS / HostOS / GuestOS), TEE key derivation and
disk encryption.

**Batch 3 — Edge infrastructure** (#211):
`docs/concepts/edge-infrastructure.md` — boundary nodes, HTTP gateway,
edge caching.

**Batch 4 — Evolution and scaling** (#212):
`docs/concepts/evolution-scaling.md` — horizontal scaling via subnet
sharding, fault tolerance, governance-driven subnet creation, forkless
protocol upgrades.

**Chain fusion deep dives** (#213): Expanded
`docs/concepts/chain-fusion/` with dedicated pages for Bitcoin
integration, ckBTC mechanics, Ethereum integration, EVM RPC, Solana RPC,
Dogecoin integration, and Exchange Rate Canister. Architecture and flow
diagrams migrated to `public/concepts/chain-fusion/`.

**Cryptography deep dives** (#214): Expanded
`docs/concepts/chain-key-cryptography.md` and
`docs/concepts/certified-data.md` with subnet keys, threshold signing
internals, and certified communication theory.

**Tokens, ledgers, and cycles** (#215): Expanded
`docs/concepts/ledgers.md` and `docs/concepts/cycles.md` with ledger
architecture, accounts, sub-accounts, cycles ledger transfer semantics,
and NNS tokenomics.

**Governance deep dives** (#216): Expanded `docs/concepts/governance.md`
and added `docs/concepts/sns-framework.md` — NNS neuron attributes and
bonuses, voting rewards formula, Neurons Fund, proposal taxonomy, SNS
framework and architecture, DAO settings, launch flow, SNS neurons and
rewards, and SNS proposals.

**Principals and canister model** (#217): Expanded
`docs/concepts/principals.md` and `docs/concepts/canisters.md` —
principal model, canister control, Wasm execution model, and
`docs/concepts/app-architecture.md`.

**Post-migration holistic review** (#218, #226):
- Navigation restructured across all concepts, guides, and references —
sentence case applied throughout, section indices completed
- Cross-reference audit: all Learn Hub outbound links replaced with
internal doc links; first-use terms linked to their concept pages
- Glossary expanded with TEE, boundary node, and cycle-related entries
- System canisters content placement corrected
- Exchange Rate Canister restructured across concept, reference, and
guide pages (#XRC commits)

**Migration infrastructure** (initial prep commits):
- `.docs-plan/learn-hub-migration.md` — agent workflow and authoring
rules for 9-batch execution
- `.docs-plan/learn-hub-navigation.md` — per-article mapping (target
file, action type, cross-link table)
- `AGENTS.md / CLAUDE.md` — Learn Hub removed from external-docs list;
linking rule updated
- `sidebar.mjs` — all new concept pages registered

## Closes

- Closes #187 — Content gap analysis: Learn Hub vs developer docs
- Closes #190 — Gap analysis: articles on learn.internetcomptuter.org vs
developer-docs `reference` and `concepts`
- Closes #226 — Post-migration holistic review (content placement, nav
structure, glossary, first-use terms)

## Sync recommendation

hand-written (all pages authored from Learn Hub source articles via
Zendesk API; no upstream repo to sync from)

<!-- Upstream: source articles fetched from learn.internetcomputer.org
via Zendesk API (2026-05-06 through 2026-05-11) -->