ADR-0003: local follows bypass AP, unified FollowCommand/FollowQuery ports, FederationRepos struct, base_url normalization

docs/adr/0003-local-follow-direct-db.md

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+# Local follows bypass ActivityPub, share storage
+
+ADR-0002 introduced `SocialIdentity` so the domain never branches on local vs remote, but the adapter (`CompositeSocialAdapter`) still routed everything through k_ap — meaning a local user following another local user triggered WebFinger resolution, HTTP signature verification, and inbox delivery to the same instance. Wasteful on any hardware, unacceptable on an N100.
+
+## Decision
+
+**Commands branch in the adapter, queries don't.**
+
+- `SocialCommand` methods in `CompositeSocialAdapter` check the `SocialIdentity` variant. Local targets get direct SQL writes to the `ap_followers`/`ap_following` tables (via a domain `FollowRepository` port). Remote targets delegate to `k_ap::ActivityPubService` as before.
+- `SocialQuery` methods go through the domain port only — a single SQL query that left-joins `ap_followers`/`ap_following` against both `users` (local) and `ap_remote_actors` (remote), returning `SocialActor` directly.
+- Local follows store the full actor URL (`https://instance.example/users/{uuid}`) in `remote_actor_url`, same format as remote follows. k_ap's AP collection endpoints read from these tables unchanged, so local relationships are visible to the fediverse automatically.
+- Local user metadata (display name, avatar) is resolved from the `users` table at query time — no duplication into `ap_remote_actors`.
+- Follow acceptance is required for both local and remote — no behavioral divergence.
+- Local follow events (`FollowRequested`, `FollowAccepted`) are not broadcast as AP activities. The fediverse discovers local relationships passively via collection endpoints.
+
+## Considered Options
+
+- **Keep routing local through k_ap** — rejected because it wastes CPU/network on self-delivery and creates an unnecessary runtime dependency on federation for local social features.
+- **Separate `local_follows` table** — rejected because it creates two sources of truth for the same concept and requires merging in collection endpoints.
+- **Insert local users into `ap_remote_actors`** — rejected because it duplicates profile data and requires sync when local users update their profile.