ci: add Forgejo Actions gate (fmt, clippy, tests, markdown) (Sam & Claude)

colibri had no CI, so a non-compiling main slipped through (the build-break PR
#23 had to fix) and the markdown gate from #22 was honor-system only.

- .forgejo/workflows/ci.yml: runs on push-to-main + PRs. Two jobs — rust
  (cargo fmt --check, clippy -D warnings, cargo test --workspace) and markdown
  (./scripts/check-format.sh).
- scripts/ci-checks.sh: same gates in one script, runnable locally before
  pushing (the workflow and humans share it).

Validated: scripts/ci-checks.sh passes end-to-end on this branch (exit 0).

NOTE: requires a registered Forgejo Actions runner with an `ubuntu-latest`
label that can pull the rust/node images. Adjust runs-on to match the runner.
Stacked on `all-checks-green` (the fmt fix) so the first CI run is green; merge
that PR first.

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

.forgejo/workflows/ci.yml

@@ -0,0 +1,41 @@
+# Forgejo Actions CI for Colibri.
+#
+# Gates every push to main and every pull request on the same checks agents are
+# expected to run locally (./scripts/ci-checks.sh): rustfmt, clippy, workspace
+# tests, and the markdown format gate. This is what would have caught the
+# build-break that PR #23 had to fix.
+#
+# Requirements (verify on the Forgejo instance):
+#   - A registered Forgejo Actions runner whose labels include `ubuntu-latest`
+#     (adjust `runs-on` below to match your runner's label if different).
+#   - The runner can pull the `rust` and `node` container images and reach
+#     crates.io / npm for dependencies.
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  rust:
+    runs-on: ubuntu-latest
+    container: rust:1.95
+    steps:
+      - uses: actions/checkout@v4
+      - name: Ensure rustfmt + clippy are present
+        run: rustup component add rustfmt clippy
+      - name: cargo fmt --check
+        run: cargo fmt --check
+      - name: cargo clippy (warnings = errors)
+        run: cargo clippy --workspace --all-targets -- -D warnings
+      - name: cargo test --workspace
+        run: cargo test --workspace
+
+  markdown:
+    runs-on: ubuntu-latest
+    container: node:20
+    steps:
+      - uses: actions/checkout@v4
+      - name: Markdown format gate
+        run: ./scripts/check-format.sh

scripts/ci-checks.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+# Run every repository gate, the same set CI runs. Use this before pushing.
+#
+#   ./scripts/ci-checks.sh
+#
+# Gates: rustfmt, clippy (warnings = errors), workspace tests, markdown format.
+
+set -eu
+
+ROOT_DIR="$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)"
+cd "$ROOT_DIR"
+
+echo "==> cargo fmt --check"
+cargo fmt --check
+
+echo "==> cargo clippy --workspace --all-targets -- -D warnings"
+cargo clippy --workspace --all-targets -- -D warnings
+
+echo "==> cargo test --workspace"
+cargo test --workspace
+
+echo "==> markdown format gate"
+./scripts/check-format.sh
+
+echo "All checks passed."