feat: social notes MCP + CLI tools (kind:1/kind:3)

[tlongwell-block]

Summary

Add 5 MCP tools and 5 CLI commands to expose kind:1 (text note) and kind:3 (contact list) global Nostr events that PR #245 already stores in the relay. Enables agents in the ACP harness to tweet.

What's included

Relay

• Bug fix: GET /api/events/{id} now returns global events (kind:0, 1, 3, 30023) with a scope-aware allowlist instead of 404ing all global events. Returns 404 (not 403) for unauthorized kinds to prevent event enumeration.
• New endpoints: GET /api/users/{pubkey}/notes (paginated kind:1 listing) and GET /api/users/{pubkey}/contact-list (latest kind:3)
• Security hardening: LIKE wildcard escaping in search_users, 200-char search query cap, limit floor/ceiling enforcement

SDK

• build_note(content, reply_to) — kind:1 text note builder with 64 KiB content limit
• build_contact_list(contacts) — kind:3 contact list builder with pubkey/relay_url/petname validation
• SdkError::InvalidInput — new error variant for input validation failures

MCP (opt-in social toolset)

• publish_note — publish kind:1 text note via WebSocket
• set_contact_list — replace kind:3 contact list via WebSocket
• get_event — fetch any global event by ID (kind:0/1/3/30023)
• get_user_notes — list user's kind:1 notes with composite cursor pagination
• get_contact_list — fetch user's latest kind:3 contact list

CLI

• publish-note, set-contact-list, get-event, get-user-notes, get-contact-list

DB

• Composite keyset cursor (before_id) for stable same-second pagination
• get_latest_global_replaceable query with NIP-16 canonical ordering
• Deterministic ORDER BY created_at DESC, id ASC tiebreaker (global change to query_events)
• global_only filter on EventQuery for defensive channel isolation

Tests

• 11 unit tests for SDK builders (happy paths, edge cases, rejection)
• 11 scope-enforcement unit tests in events.rs (allowlist logic, closed-default, empty scopes)
• 5 LIKE escaping unit tests
• 6 E2E integration tests (paginated notes, contact list replacement, event fetch)

Architecture

MCP Agent                                    CLI
    │                                          │
    ├─ publish_note ──► WS send_event (kind:1) │ ──► POST /api/events (kind:1)
    ├─ set_contact_list ► WS send_event (kind:3)│ ──► POST /api/events (kind:3)
    │                                          │
    ├─ get_event ─────► GET /api/events/{id}   │ ──► GET /api/events/{id}
    ├─ get_user_notes ► GET /api/users/{pk}/notes  ──► same
    └─ get_contact_list ► GET /api/users/{pk}/contact-list ──► same

Safety invariants

• Scope-aware allowlist: GET /api/events/{id} uses conditional scope checks — UsersRead for kind:0/3, MessagesRead for kind:1/30023, 404 for everything else (fail-closed)
• No enumeration signal: All unauthorized paths return 404 with identical message
• Input validation: hex64 validation at MCP, CLI, REST, and SDK layers; parameterized SQL throughout
• Global-only ingest: kind:1/3 are always stored with channel_id = NULL by the ingest invariant

Breaking changes

• query_events now uses ORDER BY created_at DESC, id ASC (was created_at DESC only). This adds a deterministic tiebreaker for same-second events. Existing callers (canvas, WebSocket REQ) now get stable ordering instead of arbitrary row selection.

Deferred

• Full NIP-10 threading for replies (root + reply + p-tag resolution)
• follow/unfollow convenience commands
• Global note feed endpoint (GET /api/notes)
• Desktop UI for social notes
• Global reactions on social notes

Files changed (15)

File	Change
sprout-sdk/src/lib.rs	SdkError::InvalidInput
sprout-sdk/src/builders.rs	build_note + build_contact_list + 11 tests
sprout-relay/src/api/events.rs	Allowlist fix + 11 scope tests
sprout-relay/src/api/users.rs	2 REST handlers + search hardening
sprout-relay/src/api/mod.rs	Re-exports
sprout-relay/src/router.rs	2 routes
sprout-db/src/event.rs	Composite cursor + get_latest_global_replaceable + global_only
sprout-db/src/lib.rs	Db wrapper
sprout-db/src/user.rs	LIKE escaping + 5 tests
sprout-mcp/src/server.rs	5 tools + param structs
sprout-mcp/src/toolsets.rs	Social toolset (48 tools, 8 toolsets)
sprout-cli/src/main.rs	5 commands (53 total)
sprout-cli/src/commands/social.rs	5 cmd_* functions
sprout-cli/src/commands/mod.rs	pub mod social
sprout-test-client/tests/e2e_rest_api.rs	6 E2E tests