feat(cli): real auth, delete commands, api-keys, JSON output, env override

Address the review findings on the CLI surface:

* `pic login` now prompts for username + password and POSTs to
  `/api/v1/admin/auth/login`. `--token` (and `PICLOUD_TOKEN`) still
  works for paste-a-bearer flows (CI, long-lived API keys). Falls
  back to a plain stdin read when no controlling tty is attached.
* `pic logout` revokes the session server-side and deletes the local
  credentials file. Idempotent.
* `PICLOUD_URL` / `PICLOUD_TOKEN` now override the on-disk credentials
  file for every command via `config::resolve`, not just for
  `pic login`. Matches gcloud/aws/kubectl semantics.
* New commands: `pic apps delete [--force]`, `pic apps show`,
  `pic scripts delete`, `pic api-keys mint|ls|rm`, plus top-level
  `pic invoke` / `pic deploy` shortcuts.
* `pic scripts ls` (no `--app`) now issues a single
  `GET /admin/scripts` + one `apps_list` in parallel and joins
  client-side, instead of walking N+1 per-app calls that aborted on
  the first 404 — the bug the test suite was retrying around.
* Global `--output tsv|json` flag wired through every list/show and
  through `whoami` / `logs`. TSV stays pipe-friendly; JSON is a real
  array of objects (or a flat object for single-row views).
* `whoami` and `logs` now emit labeled output instead of headerless
  tab lines, consistent with the existing `apps ls` / `scripts ls`.

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

crates/picloud-cli/src/config.rs

@@ -43,6 +43,41 @@ pub fn load() -> Result<Credentials> {
     toml::from_str(&body).with_context(|| format!("failed to parse {}", path.display()))
 }
 
+/// Resolution order used by every non-login command:
+///   1. If both `PICLOUD_URL` and `PICLOUD_TOKEN` are set (and non-empty),
+///      use them directly. Matches gcloud/aws/kubectl semantics — env
+///      wins so CI never accidentally reads a developer's stale file.
+///   2. Otherwise fall back to the on-disk credentials file.
+///
+/// Username is best-effort: env mode has no way to know the real one
+/// (no round-trip to `/auth/me`), so it shows as `"-"` in `whoami`
+/// output. Callers that need the canonical username re-fetch via
+/// `Client::auth_me`.
+pub fn resolve() -> Result<Credentials> {
+    if let (Ok(url), Ok(token)) = (std::env::var("PICLOUD_URL"), std::env::var("PICLOUD_TOKEN")) {
+        if !url.is_empty() && !token.is_empty() {
+            return Ok(Credentials {
+                url,
+                token,
+                username: "-".to_string(),
+            });
+        }
+    }
+    load()
+}
+
+/// Delete the on-disk credentials file. Idempotent — silently succeeds
+/// if the file is already gone (the user already logged out, or never
+/// logged in to begin with).
+pub fn delete() -> Result<()> {
+    let path = credentials_path()?;
+    match fs::remove_file(&path) {
+        Ok(()) => Ok(()),
+        Err(err) if err.kind() == std::io::ErrorKind::NotFound => Ok(()),
+        Err(err) => Err(err).with_context(|| format!("removing {}", path.display())),
+    }
+}
+
 pub fn save(creds: &Credentials) -> Result<()> {
     let path = credentials_path()?;
     if let Some(parent) = path.parent() {