Reference docs: Auto-generated nic CLI, config schema, and NicApp CRD

Sub-issue of #632.

Scope

Auto-generated reference content under docs/docs/references/ for the three sources of structured truth: nic CLI, NIC config schema, and the NicApp CRD. Generators live in upstream repos; this site pulls the generated markdown at build time. Reference content must be auto-generated wherever possible so it cannot drift from the code.

nic CLI reference (auto-generated)

• Source: nebari-infrastructure-core (Cobra commands in cmd/nic/)
• Generation: Cobra's built-in doc generator (cobra.GenMarkdownTree), emitted by a make docs target upstream, pulled into this site at build
• Output: one page per command (deploy, destroy, kubeconfig, validate, version) with flags, args, env vars
• No hand-edited CLI pages in this repo

NIC configuration schema (auto-generated)

• Source: Go struct tags across pkg/config/ and pkg/provider/*/config.go in nebari-infrastructure-core
• Generation: the existing plan under nebari-infrastructure-core/docs/plans/config-doc-generator/, finish and wire it in
• Output: per-provider schema pages (AWS, Hetzner, GCP, Azure, local), DNS provider config (Cloudflare), runtime flags

NicApp CRD reference (auto-generated)

• Source: CRD definition in nebari-dev/nebari-operator
• Generation: controller-gen / crd-ref-docs (or equivalent) producing markdown from the CRD schema
• Output: field-by-field reference, annotated examples

Pipeline requirements

• Generators live in the upstream repos (nebari-infrastructure-core, nebari-operator), not this repo
• nebari-docs pulls generated markdown at build time (git submodule, released artifact, or npm run docs:sync script: pick the simplest that works)
• CI in the upstream repos fails the build if generators error
• This repo's build fails if generated content is missing or stale beyond a pinned version

Acceptance criteria

• CLI reference is generated from nebari-infrastructure-core (no hand-edited CLI pages)
• Config schema is generated from struct tags (no hand-edited field lists)
• NicApp CRD reference is generated from the CRD (no hand-edited schema)
• Generation runs in CI and drift is caught automatically

Reference

Repos:

• nic CLI: https://github.com/nebari-dev/nebari-infrastructure-core
• Nebari Operator: https://github.com/nebari-dev/nebari-operator

Source in nebari-infrastructure-core:

• Existing CLI reference: docs/cli-reference.md
• Config design: docs/design-doc/implementation/07-configuration-design.md
• Config types: pkg/config/config.go, pkg/provider/*/config.go
• Config doc generator plan: docs/plans/config-doc-generator/
• Examples: examples/