feat(vars): admin CRUD API + pic vars CLI

Completes the vars half of Phase 3 end-to-end:
- vars_repo: VarOwner{Group|App} upsert/delete/list (owner-kind-specific
  SQL; ON CONFLICT restates the partial-index predicate).
- vars_api: GET/PUT/DELETE under /apps/{id}/vars and /groups/{id}/vars,
  resolve-then-require gated on App/GroupVars{Read,Write}, secrets-style
  error mapping + key/env-scope validation.
- pic vars ls/set/rm (--group|--app, --env, --json, --tombstone).
- journey test: a group var is inherited by a descendant app's
  vars::get(), and an app-level value overrides it (proximity) — green.

386 manager-core lib tests + the vars journey pass; clippy clean.

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

crates/picloud-cli/src/main.rs

@@ -144,6 +144,14 @@ enum Cmd {
         cmd: MembersCmd,
     },
 
+    /// Config vars (Phase 3) — set / list / delete group- or app-owned
+    /// env-scoped vars. Values inherit down the group tree; an app value
+    /// overrides an inherited one (proximity wins).
+    Vars {
+        #[command(subcommand)]
+        cmd: VarsCmd,
+    },
+
     /// Files inspection — list a collection's blobs, download bytes, or
     /// delete a file. Read + delete only; writes go through scripts.
     Files {
@@ -1162,6 +1170,53 @@ enum SecretsCmd {
     },
 }
 
+#[derive(Subcommand)]
+enum VarsCmd {
+    /// List the owner's OWN vars (not the resolved/inherited view).
+    Ls {
+        /// Owning group (slug or id). Mutually exclusive with `--app`.
+        #[arg(long)]
+        group: Option<String>,
+        /// Owning app (slug or id). Mutually exclusive with `--group`.
+        #[arg(long)]
+        app: Option<String>,
+    },
+
+    /// Set a var. The value is stored as a JSON string by default; pass
+    /// `--json` to parse it as raw JSON. `--tombstone` writes a deletion
+    /// marker that suppresses an inherited key.
+    Set {
+        key: String,
+        /// Ignored (but accepted) when `--tombstone` is set.
+        #[arg(default_value = "")]
+        value: String,
+        #[arg(long)]
+        group: Option<String>,
+        #[arg(long)]
+        app: Option<String>,
+        /// Environment scope (`*` = env-agnostic, the default).
+        #[arg(long)]
+        env: Option<String>,
+        /// Parse `value` as raw JSON instead of a string literal.
+        #[arg(long)]
+        json: bool,
+        /// Write a tombstone (suppress an inherited key) instead of a value.
+        #[arg(long)]
+        tombstone: bool,
+    },
+
+    /// Delete a var by key (optionally scoped to one environment).
+    Rm {
+        key: String,
+        #[arg(long)]
+        group: Option<String>,
+        #[arg(long)]
+        app: Option<String>,
+        #[arg(long)]
+        env: Option<String>,
+    },
+}
+
 #[derive(Subcommand)]
 enum AdminsCmd {
     /// List admin accounts.
@@ -1761,6 +1816,41 @@ async fn main() -> ExitCode {
         Cmd::Members {
             cmd: MembersCmd::Rm { app, user_id },
         } => cmds::members::rm(&app, &user_id).await,
+        Cmd::Vars {
+            cmd: VarsCmd::Ls { group, app },
+        } => cmds::vars::ls(group.as_deref(), app.as_deref(), mode).await,
+        Cmd::Vars {
+            cmd:
+                VarsCmd::Set {
+                    key,
+                    value,
+                    group,
+                    app,
+                    env,
+                    json,
+                    tombstone,
+                },
+        } => {
+            cmds::vars::set(
+                group.as_deref(),
+                app.as_deref(),
+                &key,
+                &value,
+                env.as_deref(),
+                json,
+                tombstone,
+            )
+            .await
+        }
+        Cmd::Vars {
+            cmd:
+                VarsCmd::Rm {
+                    key,
+                    group,
+                    app,
+                    env,
+                },
+        } => cmds::vars::rm(group.as_deref(), app.as_deref(), &key, env.as_deref()).await,
         Cmd::Files {
             cmd:
                 FilesCmd::Ls {