feat(apply): server-side enforcement of per-env approval gating (§3 M3 / §4.2)

The per-env approval gate (`[project.environments]`, `confirm = true`) was
client-side only — the policy was `#[serde(skip_serializing)]`, so a patched or
older CLI applying to a confirm-required env bypassed it entirely. This makes
the gate server-enforced, admin-gated, and audited (the deferred §4.2 piece).

- Wire: `ProjectDecl` gains `environments` (the CLI stops skip_serializing it and
  sends the selected `env` + the `--approve` set on the apply request). The
  server RE-DERIVES the gate from the request (`env_gate_check`): a
  confirm-required env not in `approved_envs` → 409 `ApprovalRequired`.
- Admin gate: an approved override additionally requires `AppAdmin`/`GroupAdmin`
  on EVERY declared node — a step up from the editor write caps an ordinary
  apply needs (reusing the admin caps per §4.2) — and emits a `tracing::info!`
  audit line. Enforced on all three handlers (single app, single group, tree);
  the check runs before any tx, so a denial (403) precedes any mutation.
- Token: the env policy folds into the TREE bound-plan token (a policy edit
  between plan and apply trips StateMoved). The single-node token is left
  unchanged (a bare live-state hash), so plan/apply still match without threading
  a project into it.
- CLI: single-node `apply`/`plan` now resolve the GOVERNING project (own block
  else nearest ancestor's) so a leaf apply carries the root's policy; `plan`
  surfaces `approvals_required`. Client-side `require_env_approval` fast-fail
  kept as UX.

Adapts the earlier feat/ownership-and-approval M5 (654e387) to main's DTOs; main
addresses tree group nodes by slug only, so the admin loop mirrors authz_tree
(app: resolve_app_id fail-closed; group: get_by_slug, skip to-create).

Threat-model note (honest scope, in the doc + code comments): this closes the
patched/older-CLI bypass and admin-gates + audits the override, but is NOT a
hermetic boundary against a hand-crafted request that OMITS the policy — the
policy is applier-supplied, not persisted server state. Full closure (persist a
`project_environments` source of truth + a server-determined env) is deferred.

Review (adversarial pass): fixed a MEDIUM (single-node `plan` didn't resolve the
governing project, so a leaf plan under-reported the gate `apply` enforces) and a
LOW (duplicate clippy attr); corrected overstated "can't bypass" wording.

Tests: ProjectDecl gate unit test; env_approval journeys
`server_enforces_the_gate_against_a_non_stock_client` (raw request → 409 without
approval, admin-approved → 200) and `approving_a_gated_apply_requires_admin`
(editor + --approve → 403). 417 lib tests + 33 CLI journeys + workspace clippy
-D warnings + fmt clean. No migration.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/picloud-cli/src/cmds/plan.rs

@@ -31,8 +31,15 @@ pub async fn run(manifest_path: &Path, env: Option<&str>, mode: OutputMode) -> R
         NodeKind::App
     };
 
+    // §3 M3: preview the gate against the GOVERNING project (own block, else the
+    // nearest ancestor's), symmetric with `apply::run` — so `pic plan --file` on
+    // a leaf still surfaces `approvals_required` for the gate the apply enforces.
+    let governing = manifest
+        .project
+        .clone()
+        .or_else(|| crate::cmds::apply::find_governing_project(manifest_path));
     let plan = client
-        .plan_node(kind, manifest.slug(), &bundle, manifest.project.as_ref())
+        .plan_node(kind, manifest.slug(), &bundle, governing.as_ref())
         .await?;
     // Record the bound-plan token so a subsequent `pic apply` can detect the
     // node changing underneath the reviewed plan (best-effort — a read-only
@@ -122,6 +129,18 @@ fn render_tree(plan: &TreePlanDto, mode: OutputMode) {
         }
     }
     table.print(mode);
+    render_approvals(&plan.approvals_required, mode);
+}
+
+/// §3 M3: surface the confirm-required environments so CI sees the gate at plan
+/// time, before an `apply --approve <env>` is needed.
+fn render_approvals(approvals_required: &[String], mode: OutputMode) {
+    if mode != OutputMode::Json && !approvals_required.is_empty() {
+        eprintln!("\nenvironments requiring explicit approval (apply with --approve <env>):");
+        for e in approvals_required {
+            eprintln!("  - {e}");
+        }
+    }
 }
 
 /// Assemble the wire bundle: scripts carry inlined source (read from
@@ -257,4 +276,5 @@ fn render(plan: &PlanDto, mode: OutputMode) {
         }
     }
     table.print(mode);
+    render_approvals(&plan.approvals_required, mode);
 }