feat: declarative project-tool foundation (pull/plan/apply/prune)

Add a server-side, atomic, declarative reconcile loop for a single app —
the foundation of the project-tool design. Developers describe an app's
scripts, routes, triggers, and secret-names in `picloud.toml`, then
`pic pull / plan / apply [--prune]` to converge live state to the manifest.

Server (manager-core):
- apply_service: a pure diff engine (compute_diff) shared by plan and
  apply, plus an ApplyService that composes the existing per-repo writes
  into ONE Postgres transaction. Identity keys mirror the DB UNIQUE
  constraints (script=lower(name); route=(method,host_kind,host,
  path_kind,path); trigger=per-kind semantic tuple; secret=name).
  Apply takes a per-app advisory lock, recomputes the diff in-tx, applies
  scripts -> routes -> triggers, prunes dependents-first, commits, then
  refreshes the route table once post-commit.
- apply_api: POST /apps/{id}/plan (AppRead) and /apps/{id}/apply.
  Apply requires the per-kind write caps the bundle exercises (all three
  when --prune), plus AppSecretsRead when it binds an email trigger.
- tx-accepting repo siblings (insert/update/delete *_tx) so the existing
  create/update/delete delegate to one SQL definition each.
- email triggers reference an inbound secret by NAME; the value is
  resolved, decrypted (AAD-bound), and re-sealed server-side at apply —
  it never travels in the manifest.

CLI (picloud-cli):
- manifest.rs (picloud.toml model), client plan/apply, and the pull/plan/
  apply commands. pull rejects filesystem-unsafe script names up front.

Safety properties enforced and tested:
- idempotent: a freshly-pulled manifest re-applies as all-NoOp.
- atomic: a mid-bundle failure rolls back with nothing written.
- routes delete-before-insert so a freed binding is reusable in one apply.
- queue one-consumer invariant held inside the shared tx.
- email triggers are never pruned, and a script that still owns an
  email/dead-letter trigger can't be pruned (the FK cascade would destroy
  the sealed secret) — refused with a pointer to `pic triggers rm`.
- plan and apply agree on unset email-secret references.

No migration: the existing schema's UNIQUE constraints serve as identity
keys. Groups, env-scoping, and the `enabled` toggle are later milestones.

Tested: manager-core lib (360) + CLI bins (27) + 8 project-tool journeys
(pull/plan/apply/prune/email+queue), all green; clippy -D warnings clean.

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

crates/picloud-cli/src/client.rs

@@ -900,6 +900,36 @@ impl Client {
             .await?;
         decode(resp).await
     }
+
+    /// `POST /api/v1/admin/apps/{id_or_slug}/plan` — diff a desired-state
+    /// bundle against the app's live state. Read-only.
+    pub async fn plan(&self, app: &str, bundle: &serde_json::Value) -> Result<PlanDto> {
+        let app = seg(app);
+        let resp = self
+            .request(Method::POST, &format!("/api/v1/admin/apps/{app}/plan"))
+            .json(bundle)
+            .send()
+            .await?;
+        decode(resp).await
+    }
+
+    /// `POST /api/v1/admin/apps/{id_or_slug}/apply` — reconcile the live
+    /// app to the bundle in one transaction.
+    pub async fn apply(
+        &self,
+        app: &str,
+        bundle: &serde_json::Value,
+        prune: bool,
+    ) -> Result<ApplyReportDto> {
+        let app = seg(app);
+        let body = serde_json::json!({ "bundle": bundle, "prune": prune });
+        let resp = self
+            .request(Method::POST, &format!("/api/v1/admin/apps/{app}/apply"))
+            .json(&body)
+            .send()
+            .await?;
+        decode(resp).await
+    }
 }
 
 /// `POST /api/v1/admin/auth/login` — sits outside the `Client` because
@@ -924,6 +954,50 @@ pub async fn auth_login(url: &str, username: &str, password: &str) -> Result<Log
 
 // ---------- DTOs (CLI-local, wire-shape-matched) ----------
 
+/// Response of `POST .../plan`: per-resource diffs grouped by kind.
+#[derive(Debug, Deserialize)]
+pub struct PlanDto {
+    #[serde(default)]
+    pub scripts: Vec<ChangeDto>,
+    #[serde(default)]
+    pub routes: Vec<ChangeDto>,
+    #[serde(default)]
+    pub triggers: Vec<ChangeDto>,
+    #[serde(default)]
+    pub secrets: Vec<ChangeDto>,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct ChangeDto {
+    pub op: String,
+    pub key: String,
+    #[serde(default)]
+    pub detail: Option<String>,
+}
+
+/// Response of `POST .../apply`: counts of what changed.
+#[derive(Debug, Default, Deserialize)]
+pub struct ApplyReportDto {
+    #[serde(default)]
+    pub scripts_created: u32,
+    #[serde(default)]
+    pub scripts_updated: u32,
+    #[serde(default)]
+    pub scripts_deleted: u32,
+    #[serde(default)]
+    pub routes_created: u32,
+    #[serde(default)]
+    pub routes_updated: u32,
+    #[serde(default)]
+    pub routes_deleted: u32,
+    #[serde(default)]
+    pub triggers_created: u32,
+    #[serde(default)]
+    pub triggers_deleted: u32,
+    #[serde(default)]
+    pub warnings: Vec<String>,
+}
+
 #[allow(dead_code)]
 #[derive(Debug, Deserialize)]
 pub struct AuthMeDto {