feat(plugins): P6 — developer experience (D44/D45/D47/D48/D60/D62)

[aqib-rx]

Summary

P6 — Developer Experience for the plugin platform (single combined plan, 17 commits).

• D44/D45 — create-nextly-app --template plugin + embedded /dev playground (minimal Nextly-on-SQLite, HMR; src/ published, dev/ never).
• D47 — typed codegen: generate:types emits permissions/events maps; PermissionSlug/EventName narrow via GeneratedTypes (string fallback → non-breaking).
• D60 — generated admin component import map; run-once auto-registration relaxed to per-module.
• D48 — nextly plugins list/info introspection + author guide / API reference / error reference docs.
• D62 — @nextlyhq/plugin-sdk README alpha/stability policy.

Dogfooded by form-builder (R4). New public surface is @experimental (D55).

Test Plan

• build + check-types clean across nextly / admin / plugin-sdk / plugin-form-builder / create-nextly-app
• nextly unit = 405-failure baseline (0 new); integration = 3 pre-existing (0 new)
• admin = 51-failure baseline (0 new, +3 tests); form-builder 23/23; plugin-sdk 7/7; create-nextly-app 107/107 (+ scaffold smoke)
• real-environment /dev boot smoke (not run in-sandbox)

Base is feat/plugin-platform (not main). P6 stacks on the unmerged P0–P5 stack — land in order. No changeset on a phase branch (per workflow).

[github-actions]

PR title fails Conventional Commits check

Unknown scope "plugins" found in pull request title "feat(plugins): P6 — developer experience (D44/D45/D47/D48/D60/D62)". Scope must match one of: nextly, admin, client, ui, adapter-postgres, adapter-mysql, adapter-sqlite, adapter-drizzle, storage-s3, storage-vercel-blob, storage-uploadthing, plugin-form-builder, create-nextly-app, eslint-config, prettier-config, tsconfig, playground, root, ci, docs, deps, release.

Examples of valid titles:

• feat(admin): add role manager dialog
• fix(adapter-postgres): handle connection pool exhaustion
• chore(deps): bump zod to 4.2.0