docs: scaffold documentation information architecture (Phase 1)

Add the docs/ skeleton for the full docs implementation: getting-started,
architecture, guides, reference, and vision sections, with a nav/TOC home
page. Every page is a stub carrying its heading outline and pointers to the
source material to be migrated in Phase 2 (content).

docs/nips/, docs/spec/, and the loose design docs stay at their current
paths (55 references from code, tests, and migrations outside docs/);
reference/nips.md and reference/design-docs.md index them instead.

Root GitHub-convention files are untouched. ARCHITECTURE/NOSTR/TESTING/
RELEASING/VISION* remain in place this phase and will become pointer files
in Phase 2.

Co-authored-by: npub19zza5yyr075j4vvlg2drsh2xe0xy3dqxhfchlgtw8vryglrry3gq8q7tzk <2885da10837fa92ab19f429a385d46cbcc48b406ba717fa16e3b06447c632450@sprout-oss.stage.blox.sqprod.co>
Signed-off-by: npub19zza5yyr075j4vvlg2drsh2xe0xy3dqxhfchlgtw8vryglrry3gq8q7tzk <2885da10837fa92ab19f429a385d46cbcc48b406ba717fa16e3b06447c632450@sprout-oss.stage.blox.sqprod.co>

docs/reference/cli.md

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+# CLI Reference
+
+> **Status: stub — Phase 1 (structure).** Content to be written in Phase 2.
+>
+> **Scope:** Command-by-command reference for the `buzz` CLI, derived from --help output and verified against `crates/buzz-cli` source (README has known drift).
+
+## Outline
+
+- Global flags, env vars (BUZZ_RELAY_URL, BUZZ_PRIVATE_KEY, BUZZ_AUTH_TAG), exit codes
+- Command groups: messages, channels, canvas, reactions, dms, users, workflows, feed, social, repos, upload, mem
+- Examples per group
+
+## Source material
+
+- `buzz --help` and per-group `--help` (primary)
+- `crates/buzz-cli/src/` (verify — do not trust `crates/buzz-cli/README.md`)

docs/reference/configuration.md

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+# Configuration Reference
+
+> **Status: stub — Phase 1 (structure).** Content to be written in Phase 2.
+>
+> **Scope:** All environment variables and config knobs for relay, CLI, and agent harness.
+
+## Outline
+
+- Relay configuration
+- CLI configuration
+- Agent harness (buzz-acp) configuration incl. BUZZ_ACP_NO_MEMORY
+- Desktop app settings (pointer)
+
+## Source material
+
+- `TESTING.md` §Configuration reference
+- `deploy/compose/README.md` env tables
+- crate sources for env var reads

docs/reference/design-docs.md

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+# Design Documents Index
+
+> **Status: stub — Phase 1 (structure).** Content to be written in Phase 2.
+>
+> **Scope:** Index of the loose design docs and formal specs (kept at their current paths — referenced by code/tests; do not move).
+
+## Outline
+
+- `docs/MCP_DRIVEN_HOOKS.md` — MCP-driven lifecycle hooks
+- `docs/bridge-channel-window.md` — bridge /query channel window (defers to NIP-CW)
+- `docs/git-on-object-storage.md` — git refs over object storage (formal spec, pairs with docs/spec/GitOnObjectStore.tla)
+- `docs/mesh-llm-local-build.md` — mesh LLM local build prereqs
+- `docs/multi-tenant-relay.md` — multi-tenant relay formal spec (pairs with docs/spec/MultiTenantRelay.tla, MultiTenantAuth.spthy)
+- `docs/multi-tenant-conformance.md` — multi-tenant conformance checklist
+
+## Source material
+
+- `docs/*.md` loose files
+- `docs/spec/` TLA+/Tamarin models

docs/reference/known-limitations.md

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+# Known Limitations
+
+> **Status: stub — Phase 1 (structure).** Content to be written in Phase 2.
+>
+> **Scope:** Honest list of current gaps and stubbed features. Goal: no surprises for operators or contributors.
+
+## Outline
+
+- Relay limitations (e.g. rate limiting unenforced)
+- Workflow stubs (WF-07/WF-08)
+- Client/platform gaps
+- Docs debt (empty GOVERNANCE.md pointer file, buzz-cli README drift)
+
+## Source material
+
+- `ARCHITECTURE.md` §9 Known Limitations
+- `crates/buzz-conformance/LIMITS.md`
+- fable01's discrepancy list (survey)

docs/reference/nips.md

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+# Buzz NIPs Index
+
+> **Status: stub — Phase 1 (structure).** Content to be written in Phase 2.
+>
+> **Scope:** Index of the 13 Buzz protocol extensions in ../nips/ (kept at docs/nips/ — referenced by code and tests; do not move). One-line summary + status per NIP. NIP-CW is normative for channel-window behavior (bridge-channel-window.md defers to it).
+
+## Outline
+
+- Table: NIP id → title → one-line summary → status
+- Reading order / dependency notes
+
+## Source material
+
+- `docs/nips/NIP-*.md` (13 files)