CI: remove k8s stages, fix the Docker-level pipeline green

Survey + fixes so the pipeline passes at the Docker level (no k8s).

- Remove k8s: drop the `sandbox-k8s` job (kind/Calico/--features k8s-tests) and the
  "Helm chart lints" gate step. release.yml was already k8s-clean.
- Rust job:
  - `cargo fmt --all` — fix pre-existing formatting drift (fmt --check was failing).
  - clippy -D warnings: fix 3 lib warnings (cm-brain sort_by_key→Reverse, cm-api
    fleet.rs doc list indentation, node_rules map_or→is_none_or).
  - Regenerate the .sqlx offline cache (was missing the cm-runtime run_loop test
    query → offline compile failed). DB-backed tests use testcontainers at runtime.
  - Set SQLX_OFFLINE=true on the rust + e2e jobs so query! macros compile against
    the committed cache deterministically (no DB needed at compile time).
- Frontend job:
  - Fix the 1 ESLint error (useAgentTelemetry: no setState-synchronously-in-effect;
    tag the slice with agentId + derive null on mismatch).
  - Fix 2 stale panel-params tests (`terminal` is a valid app id now; assert the
    current APP_IDS + use a genuinely-unknown id for the reject case).

Verified locally: fmt clean, clippy --all-targets -D warnings clean (offline),
frontend lint 0 errors, tsc clean, 86/86 frontend tests pass, build OK.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

crates/cm-db/src/repo/agents.rs

@@ -296,14 +296,18 @@ pub async fn hard_purge(pool: &PgPool, agent_id: AgentId) -> Result<PurgeCounts,
     .bind(aid)
     .execute(&mut *tx)
     .await?;
-    sqlx::query("DELETE FROM messages WHERE session_id IN (SELECT id FROM sessions WHERE agent_id = $1)")
-        .bind(aid)
-        .execute(&mut *tx)
-        .await?;
-    sqlx::query("DELETE FROM agent_runs WHERE session_id IN (SELECT id FROM sessions WHERE agent_id = $1)")
-        .bind(aid)
-        .execute(&mut *tx)
-        .await?;
+    sqlx::query(
+        "DELETE FROM messages WHERE session_id IN (SELECT id FROM sessions WHERE agent_id = $1)",
+    )
+    .bind(aid)
+    .execute(&mut *tx)
+    .await?;
+    sqlx::query(
+        "DELETE FROM agent_runs WHERE session_id IN (SELECT id FROM sessions WHERE agent_id = $1)",
+    )
+    .bind(aid)
+    .execute(&mut *tx)
+    .await?;
     c.sessions = sqlx::query("DELETE FROM sessions WHERE agent_id = $1")
         .bind(aid)
         .execute(&mut *tx)
@@ -325,10 +329,22 @@ pub async fn hard_purge(pool: &PgPool, agent_id: AgentId) -> Result<PurgeCounts,
         .rows_affected();
 
     // Inter-agent threads, queued mail, oauth flows.
-    sqlx::query("DELETE FROM thread_messages WHERE from_agent = $1").bind(aid).execute(&mut *tx).await?;
-    sqlx::query("DELETE FROM thread_participants WHERE agent_id = $1").bind(aid).execute(&mut *tx).await?;
-    sqlx::query("DELETE FROM outbox WHERE agent_id = $1").bind(aid).execute(&mut *tx).await?;
-    sqlx::query("DELETE FROM oauth_states WHERE agent_id = $1").bind(aid).execute(&mut *tx).await?;
+    sqlx::query("DELETE FROM thread_messages WHERE from_agent = $1")
+        .bind(aid)
+        .execute(&mut *tx)
+        .await?;
+    sqlx::query("DELETE FROM thread_participants WHERE agent_id = $1")
+        .bind(aid)
+        .execute(&mut *tx)
+        .await?;
+    sqlx::query("DELETE FROM outbox WHERE agent_id = $1")
+        .bind(aid)
+        .execute(&mut *tx)
+        .await?;
+    sqlx::query("DELETE FROM oauth_states WHERE agent_id = $1")
+        .bind(aid)
+        .execute(&mut *tx)
+        .await?;
     c.connections = sqlx::query("DELETE FROM app_connections WHERE agent_id = $1")
         .bind(aid)
         .execute(&mut *tx)
@@ -339,7 +355,10 @@ pub async fn hard_purge(pool: &PgPool, agent_id: AgentId) -> Result<PurgeCounts,
         .execute(&mut *tx)
         .await?
         .rows_affected();
-    sqlx::query("DELETE FROM usage_events WHERE agent_id = $1").bind(aid).execute(&mut *tx).await?;
+    sqlx::query("DELETE FROM usage_events WHERE agent_id = $1")
+        .bind(aid)
+        .execute(&mut *tx)
+        .await?;
 
     // Finally the agent itself (cascades the rest).
     let n = sqlx::query("DELETE FROM agents WHERE id = $1")