fix: use absolute worktree paths, check sqlite3 availability

- worktreePath() now returns absolute path using findMainRepoDir()
- Fixes 'cannot change to worktrees/...' error from inside worktree
- test-worker.sh now checks sqlite3 is available before running

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/worker/tests/test-worker.sh

@@ -34,9 +34,18 @@ TEST_DIR=$(mktemp -d)
 TEST_REPO="$TEST_DIR/repo"
 ORIG_DIR="$(pwd)"
 
-# Set up SQLite library path
-SQLITE_LIB=$(nix-build '<nixpkgs>' -A sqlite.out --no-out-link 2>/dev/null)/lib
-export LD_LIBRARY_PATH="${SQLITE_LIB}:${LD_LIBRARY_PATH:-}"
+# Set up SQLite library and binary paths
+SQLITE_OUT=$(nix-build '<nixpkgs>' -A sqlite.out --no-out-link 2>/dev/null)
+if [[ -d "${SQLITE_OUT}" ]]; then
+    export LD_LIBRARY_PATH="${SQLITE_OUT}/lib:${LD_LIBRARY_PATH:-}"
+    export PATH="${SQLITE_OUT}/bin:${PATH}"
+fi
+
+# Verify sqlite3 is available
+if ! command -v sqlite3 &>/dev/null; then
+    echo "ERROR: sqlite3 not found. Run tests with: nix-shell -p sqlite --run 'bash $0'"
+    exit 1
+fi
 
 cleanup() {
     cd "$ORIG_DIR"
@@ -369,17 +378,10 @@ echo "## Invalid State Transitions"
 run_worker spawn --taskId=test-invalid --fromBranch=master > /dev/null
 run_worker start --task=test-invalid > /dev/null
 
-# NOTE: Should return exit code 3 (ExitInvalidTransition) but currently returns 1
-# See skills-lxb9 for fix
 output=$(run_worker approve --taskId=test-invalid 2>&1)
 exit_code=$?
-if [[ "$exit_code" != "0" ]]; then
-    echo -e "${GREEN}PASS${NC}: Approve from WORKING fails (exit code: $exit_code)"
-    ((PASSED++))
-else
-    echo -e "${RED}FAIL${NC}: Approve from WORKING should fail"
-    ((FAILED++))
-fi
+assert_exit_code "Approve from WORKING returns ExitInvalidTransition" "3" "$exit_code"
+assert_output_contains "Approve error message" "Cannot approve" "$output"
 
 # --- Review-Gate Integration ---
 echo ""

src/worker/utils.nim

@@ -11,10 +11,6 @@ proc branchName*(taskId: string): string =
   ## Get the feature branch name for a task
   &"feat/{taskId}"
 
-proc worktreePath*(taskId: string): string =
-  ## Get the worktree path for a task
-  &"{WorktreesDir}/{taskId}"
-
 proc findMainRepoDir*(): string =
   ## Find the main repository directory, even when running from a worktree.
   ## Uses git to find the common git directory, then derives the main repo.
@@ -34,6 +30,11 @@ proc findMainRepoDir*(): string =
                    else: getCurrentDir() / gitCommonDir
   result = parentDir(mainGitDir)
 
+proc worktreePath*(taskId: string): string =
+  ## Get the absolute worktree path for a task.
+  ## Uses repo root to ensure path works from any directory.
+  findMainRepoDir() / WorktreesDir / taskId
+
 proc getMainRepoBusDbPath*(): string =
   ## Get the absolute path to bus.db in the main repository.
   ## Works correctly even when called from a worktree.