chore(config): gate cargo test in pre-push on Rust changes

Add `cargo test --quiet` to the pre-push Rust block (sharing clippy's
target/ guard) so the suite runs automatically on every push touching
server/. Nothing ran the tests before — pre-push did only fmt/clippy/deny
and there is no CI — so a Rust regression could reach main unverified.

Document the resulting agent-spawn rule in team-patterns.md: don't have
implementation agents pre-run fmt/clippy/test pre-emptively, since the push
gate now enforces all three. The gate is authoritative; the lead patches any
fallout at push.

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

.claude/rules/team-patterns.md

@@ -31,3 +31,23 @@ When leading a team (workshop, batch, or any multi-agent session):
 - If an agent has not sent a message in ~20 minutes, ping them for a status update.
 - **Bottleneck detection:** if other agents are idle and waiting on one agent's output, that agent's silence is a red flag — check on them immediately, do not wait for the next natural message.
 - When checking on a stuck agent, offer to reassign the task or pull in another agent to help.
+
+## Agent verification — don't duplicate the push gate
+
+The pre-push hook (`.config/hooks/pre-push`) is the source of truth for Rust
+verification and **runs on every push the lead makes** when `server/` changed:
+`cargo fmt --check`, `cargo clippy --all-targets -- -D warnings`, and `cargo test`
+(plus `cargo deny`, ruff, JSON validation, systems.db stamp). There is no CI (no
+`.gitea`/`.github`/`.forgejo` workflows) — the push gate is the only automatic
+verification, so it is deliberately comprehensive.
+
+Therefore, when spawning implementation agents, do **not** tell them to run
+`cargo fmt`, `cargo clippy`, or `cargo test` pre-emptively — the push gate enforces
+all three, so it is pure duplication. Worse, an agent running a *weaker* check (e.g.
+plain `cargo clippy` without `-D warnings`) reports a false "clean". Let agents write
+code; the gate is authoritative.
+
+On a gate failure at push: fmt auto-fixes (`cargo fmt`); clippy is a quick lead patch;
+a `cargo test` failure is a real regression — fix it, or SendMessage the still-alive
+agent to fix it in-context. Net: agents verify nothing the gate already covers, and the
+lead lets the gate catch fallout on push.

.config/hooks/pre-push

@@ -97,8 +97,19 @@ elif command -v cargo >/dev/null 2>&1 && [ -d "$REPO_ROOT/server" ]; then
         else
             echo "pre-push: clippy — OK"
         fi
+
+        # cargo test — the ONLY automatic correctness gate: nothing else (no CI
+        # workflows exist) runs the suite, so without this a Rust regression
+        # reaches main unverified. Gated on server/ changes; shares the target/
+        # guard with clippy so a cold worktree isn't forced into a full build.
+        echo "pre-push: checking Rust (cargo test)..."
+        if ! (cd "$REPO_ROOT/server" && cargo test --quiet 2>&1); then
+            ERRORS=$((ERRORS + 1))
+        else
+            echo "pre-push: cargo test — OK"
+        fi
     else
-        echo "pre-push: skipping clippy (no target/ — run 'cargo build' once to enable)"
+        echo "pre-push: skipping clippy + test (no target/ — run 'cargo build' once to enable)"
     fi
 
     # --- Rust dependency audit (cargo deny) — requires deny.toml config ---