Locked-account profiles: private = stub + Pending follow flow

Replaces the earlier 404-for-private model with Mastodon-style locked
accounts. A private profile now returns 200 with a stub layout and
gates content behind follow approval. Default for new users flips from
'public' to 'private' to align with trails.cool's privacy-first
content defaults.

Schema:
- users.profile_visibility default flipped to 'private'. Existing rows
  remain 'public' (backfill on first migration handled them).

Follow API (follow.server.ts):
- followUser now creates Pending (accepted_at = NULL) against private
  targets and Accepted against public targets — no more refusal.
- New: countPendingFollowRequests, listPendingFollowRequests,
  approveFollowRequest, rejectFollowRequest. Approve/reject are
  owner-bound: only the followed user can act on their own incoming
  requests.
- countFollowers / countFollowing / listFollowers / listFollowing now
  filter to accepted-only relations.

Loader (users.$username.tsx):
- Drops the 404 paths. New canSeeContent flag = isOwn ||
  profile_visibility='public' || (followState.following === true).
- When canSeeContent=false, render a stub: header + 🔒 badge + body
  copy + Request-to-follow / sign-in CTA. Routes/activities sections
  are not rendered.

UI:
- FollowButton gains a "Request to follow" / "Requested" state for
  private targets via a new isPrivateTarget prop. Cancel-request reuses
  the unfollow endpoint.
- New /follows/requests page lists incoming Pending requests with
  Approve / Reject buttons.
- New API routes: POST /api/follows/:id/approve and /reject.
- Navbar shows a count badge linking to /follows/requests when
  pending > 0.

Privacy manifest already documents the follows relation; no changes
needed (the locked-account semantics don't add new data — same row,
different lifecycle).

Specs / design (social-feed change):
- public-profiles delta rewritten around the four-mode locked model
  (public, private+anon, private+pending, private+accepted) with
  scenarios for each.
- social-follows delta gains Pending lifecycle requirements (auto vs.
  manual accept, approve/reject endpoints, pending request management,
  Pending follows do not contribute to feed).
- design.md decision section reflects the new model and rationale for
  default-private; non-goal "locked-local-accounts as a follow-up" is
  removed since this change ships it.

Tests:
- follow.integration.test.ts: pending-against-private, approve flips
  to accepted, reject deletes, owner-bound enforcement.
- e2e/social.test.ts: full Request → Pending → Approve → full-view
  flow, plus stub-for-anonymous and /follows/requests auth gate.

Supersedes PR #309 (closed): the empty-public-profile 200 is now a
side-effect of the new render path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

openspec/changes/social-feed/proposal.md

@@ -6,17 +6,18 @@ This change ships the *local* social layer: follows between users on the same Jo
 
 ## What Changes
 
-- Add an explicit `users.profile_visibility` setting (`'public' | 'private'`, default `'public'`). Today profile-publicness is implicit (derived from "has any public content"); making it explicit unifies the mental model with activity/route visibility, gives users a real toggle for "be discoverable at all," and gates future federation cleanly. Existing users migrate to `'public'`.
-- Users SHALL be able to follow another *local* user (same instance) by clicking a Follow button on the user's profile page. Local public profiles auto-accept the follow.
-- A signed-in user SHALL be able to view a **social feed** of public activities from the users they follow, reverse-chronological, at a dedicated `/feed` route linked from the nav.
+- Add an explicit `users.profile_visibility` setting (`'public' | 'private'`). New accounts default to `'private'` (matches trails.cool's privacy-first content defaults); existing accounts are backfilled to `'public'` so deploy doesn't lock anyone down. `private` is functionally Mastodon's "locked" account: profile renders a stub with a Request-to-follow button for non-followers; only accepted followers see content; follows land Pending until the owner approves.
+- Users SHALL be able to follow another *local* user (same instance) by clicking a Follow / Request-to-follow button on the user's profile page. Public targets auto-accept; private targets create a Pending row that the owner approves or rejects from `/follows/requests`.
+- A signed-in user SHALL have a `/follows/requests` page listing all incoming Pending requests with Approve / Reject actions; the navbar shows a count badge linking to that page.
+- A signed-in user SHALL be able to view a **social feed** of public activities from the users they follow with an accepted relation, reverse-chronological, at a dedicated `/feed` route linked from the nav.
 - The logged-in home (`/`) SHALL link prominently to the new social feed; personal dashboard content stays as-is for now.
-- Public profile pages SHALL show follower and following counts and a Follow / Unfollow toggle for the viewing user.
-- Privacy: the follow relationship on a single instance is queryable (follower/following lists are public) matching Mastodon-style conventions. Only `public` activities appear in the feed — `unlisted` and `private` stay out even if you follow the owner.
+- Profile pages SHALL show follower and following counts (accepted-only) and a context-aware Follow control (Follow / Request to follow / Requested / Unfollow).
+- Privacy: follower/following counts and lists are public per instance. Only `public` activities appear in the feed; pending follows don't contribute content.
 - Privacy manifest: documents the new `follows` relation as data the instance retains about who follows whom.
 - **Forward-compatible schema**: `follows` is keyed by an `actor_iri TEXT` column even though all rows are local now (local user IRIs look like `https://{DOMAIN}/users/{username}`). When `social-federation` lands, remote IRIs go in the same column with no migration.
 - **Out of scope** (tracked as follow-ups):
   - ActivityPub federation primitives — `social-federation`. Goal there is "Mastodon can follow a trails account" inbound and "trails can follow other trails instances" outbound.
-  - Locked local accounts (manual follow approval) — `locked-local-accounts`. The current `'public' | 'private'` enum is intentionally minimal so the locked enum value (or a separate `users.locked` flag) can be added cleanly later.
+  - A unified notification UI. The follow-request count badge is a one-off; broader notifications (e.g., "your follow request was approved", "new public activity from people you follow") will be designed in a follow-up.
 
 ## Capabilities