feat(scripts): add agent-worktree library with derive_slug (ref #83)

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

scripts/lib/agent-worktree-lib.sh

@@ -0,0 +1,22 @@
+# shellcheck shell=bash
+# scripts/lib/agent-worktree-lib.sh
+# Helpers for scripts/agent-worktree.sh. Sourced, never executed.
+
+set -uo pipefail
+
+# Slugify a free-text title into a branch-safe slug.
+# Rules: lowercase, ASCII-fold via iconv, non-[a-z0-9] -> '-', collapse runs,
+# trim leading/trailing '-', max 40 chars, fallback 'issue' when empty.
+derive_slug() {
+  local raw="${1:-}"
+  local s
+  s=$(printf '%s' "$raw" | iconv -f UTF-8 -t ASCII//TRANSLIT 2>/dev/null || printf '%s' "$raw")
+  s=$(printf '%s' "$s" | tr '[:upper:]' '[:lower:]')
+  s=$(printf '%s' "$s" | sed -E 's/[^a-z0-9]+/-/g; s/^-+//; s/-+$//')
+  if [[ ${#s} -gt 40 ]]; then
+    s="${s:0:40}"
+    s="${s%-}"
+  fi
+  if [[ -z "$s" ]]; then s="issue"; fi
+  printf '%s' "$s"
+}

scripts/tests/test-agent-worktree.sh

@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+# Test harness for scripts/agent-worktree.sh
+# Each `test_*` function is auto-discovered and run in a subshell.
+set -uo pipefail
+
+REPO_ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
+LIB="$REPO_ROOT/scripts/lib/agent-worktree-lib.sh"
+SCRIPT="$REPO_ROOT/scripts/agent-worktree.sh"
+GH_MOCK="$REPO_ROOT/scripts/tests/fixtures/gh-mock.sh"
+
+pass=0
+fail=0
+failed_names=()
+
+run_test() {
+  local name="$1"
+  local out
+  if out=$(set -e; "$name" 2>&1); then
+    echo "OK   $name"
+    pass=$((pass+1))
+  else
+    echo "FAIL $name"
+    echo "$out" | sed 's/^/     /'
+    fail=$((fail+1))
+    failed_names+=("$name")
+  fi
+}
+
+assert_eq() {
+  local expected="$1" actual="$2" label="${3:-value}"
+  if [[ "$expected" != "$actual" ]]; then
+    echo "$label mismatch: expected '$expected' got '$actual'" >&2
+    return 1
+  fi
+}
+
+assert_contains() {
+  local haystack="$1" needle="$2"
+  if [[ "$haystack" != *"$needle"* ]]; then
+    echo "expected to contain '$needle' in: $haystack" >&2
+    return 1
+  fi
+}
+
+# Tests below
+
+test_derive_slug_basic() {
+  source "$LIB"
+  assert_eq "add-tier-manifest-helper-for-apt-staging" "$(derive_slug 'Add tier-manifest helper for APT staging')" "basic slug"
+}
+
+test_derive_slug_accents() {
+  source "$LIB"
+  assert_eq "migration-verification-a-valider" "$(derive_slug 'Migration vérification à valider')" "accents"
+}
+
+test_derive_slug_truncate_40() {
+  source "$LIB"
+  local out
+  out=$(derive_slug 'this title is intentionally far too long to fit in forty characters')
+  assert_eq "40" "${#out}" "length"
+  assert_eq "this-title-is-intentionally-far-too-long" "$out" "truncated value"
+}
+
+test_derive_slug_empty_falls_back() {
+  source "$LIB"
+  assert_eq "issue" "$(derive_slug '')" "empty input"
+  assert_eq "issue" "$(derive_slug '日本語のみ')" "all non-ASCII"
+}
+
+# Auto-discover and run
+mapfile -t tests < <(declare -F | awk '{print $3}' | grep '^test_')
+for t in "${tests[@]}"; do run_test "$t"; done
+
+echo "---"
+echo "passed: $pass  failed: $fail"
+exit $((fail > 0))