feat(scripts): group-owned script admin API + pic scripts … --group

Phase 4-lite C2. Lets a group own scripts (templates inherited by descendant
apps), with the create/list/manage surface — but not yet the inherited
resolution (binding + runtime), which is C3.

Capabilities: add `GroupScriptsRead` (viewer+ on the group → script:read) and
`GroupScriptsWrite` (editor+ → script:write), mirroring the group-vars tier and
resolved through the same group-ancestor walk.

API:
  * New `group_scripts_api`: `POST/GET /groups/{id}/scripts` — create a
    group-owned endpoint script and list a group's own (non-inherited) rows.
    Phase 4-lite is endpoint-only and self-contained: `kind=module` and any
    `import` are rejected (group modules + the lexical resolver are Phase 4b).
    Owner resolved first (slug-or-uuid); capability bound to the resolved id.
  * The by-id `/scripts/{id}` get/update/delete/logs handlers are now
    owner-polymorphic via a `script_cap` helper: app-owned scripts gate on
    `App*` exactly as before; group-owned on `GroupScripts*`. This is what
    makes `deploy --group` idempotent (update reuses the by-id PUT) and lets a
    group script be deleted by id. (C1 had these fail closed for groups.)

Repo: `list_for_group(group_id)` (the group's own rows).

CLI: `pic scripts ls --group <g>`, `pic scripts deploy --group <g>` (create or
update by name; `--app`/`--group` are mutually exclusive, exactly one
required). `pic scripts delete <id>` already works for group scripts via the
owner-polymorphic by-id route.

Live-validated against the dev DB: create → update (v2 via the by-id PUT) →
list → delete, plus module rejection and the polymorphic row shape
(`app_id NULL`, `group_id` set). Group scripts still can't be routed/triggered
or invoked — that lands in C3.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/shared/src/lib.rs

@@ -86,7 +86,7 @@ pub use realtime::{BroadcasterError, NoopRealtimeBroadcaster, RealtimeBroadcaste
 pub use realtime_authority::{DenyAllRealtimeAuthority, RealtimeAuthority, SubscribeDenied};
 pub use route::{DispatchMode, HostKind, PathKind, Route};
 pub use sandbox::ScriptSandbox;
-pub use script::{Script, ScriptKind};
+pub use script::{Script, ScriptKind, ScriptOwner};
 pub use sdk_cx::SdkCallCx;
 pub use secrets::{
     validate_secret_name, NoopSecretsService, SecretsError, SecretsListPage, SecretsService,