Reduce bundle size: tree-shakeable relations & slimmer normalization

[CodeDredd]

Analysis (v2, dist/index.mjs = 48.4 kB min / ~16 kB brotli with all exports, ~11.7 kB brotli in a real app bundle)

Measured with an esbuild metafile over src/index.ts (externals: pinia, vue, uuid, nanoid):

Contributor	minified
query/Query.ts	12.2 kB
relation attributes (all 11)	10.6 kB — morphs alone 4.9 kB, belongsToMany/hasManyThrough/hasManyBy 2.9 kB
model/Model.ts	9.8 kB
repository/Repository.ts	3.0 kB
@pinia-orm/normalizr + Schema	3.9 kB
support/Utils	2.4 kB

External packages are NOT the problem — the only bundled dependency is our own normalizr fork (~1 kB brotli). Everything else is core code.

Verified dead ends:

• sideEffects: false: zero effect (48 381 → 48 381 bytes) — the dist is flat-bundled and every class is reachable from Model/Query, so per-module shaking has nothing to drop.
• Making normalizr external: only moves bytes, users install & load it anyway.

Why nothing shakes today

Model exposes every relation as a static method (this.hasMany(...)), so all 11 relation classes are statically reachable from any app that touches Model — bundlers cannot drop method bodies. Same for Query's instanceof MorphTo/BelongsToMany handling.

Proposal

1. Tree-shakeable relation factories (target: 3.0, or additive in 2.x with the static methods deprecated):

   import { hasMany, morphMany } from 'pinia-orm'
   static fields () { return { posts: hasMany(() => Post, 'userId') } }

   Each factory imports only its relation class. Apps without morph relations save ~4.9 kB min (~1.5 kB brotli), without the exotic many-relations another ~2.9 kB min. Query's relation handling needs to dispatch via the relation instances instead of instanceof imports.
2. Purpose-built normalization replacing the generic normalizr fork (~3.9 kB min potential, high effort/risk — separate evaluation).
3. Keep measuring: the esbuild-metafile analysis should become a repeatable script so regressions show up in PRs.

Not a 2.0.0 blocker — the release is API-frozen; this is the follow-up plan with real numbers.