refactor: Remove dead code and stale references (#2062)

Remove orphaned sh/test/fixtures/ directory. These shell fixture files
(_shared_agent_assertions.sh, hetzner/_env.sh, hetzner/_api_assertions.sh,
digitalocean/_env.sh, digitalocean/_api_assertions.sh) were part of a mock
test harness (mock.sh) that was removed from the repository. The fixture
files reference `assert_api_called` and `MOCK_LOG` variables that are never
defined anywhere, confirming they are unreachable dead code.

Scan results:
- Dead code (sh/test/fixtures/): 5 orphaned fixture files removed
- Dead code (sh/shared, packages/cli/src/): none found
- Stale references to non-existent files: none found
- Python usage (python3 -c / python -c): none found
- Duplicate utilities across cloud modules: loadTokenFromConfig pattern
  exists in hetzner/daytona/digitalocean but reads from different cloud-
  specific config paths — cannot be consolidated (confirmed intentional)
- Stale comments: none found beyond those already fixed in prior PRs

-- qa/code-quality

Co-authored-by: spawn-qa-bot <qa@openrouter.ai>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

sh/test/fixtures/_shared_agent_assertions.sh

@@ -1,51 +0,0 @@
-#!/bin/bash
-# Shared per-agent install assertions
-# Verifies each agent script uses the correct install method
-#
-# Source this file and call assert_agent_install CLOUD AGENT. Expects:
-#   MOCK_LOG  — path to the mock call log
-#   PASSED / FAILED — counters (updated in-place)
-#   GREEN / RED / NC — color codes
-
-# Internal: assert a grep pattern appears in MOCK_LOG
-_assert_install_pattern() {
-    local pattern="$1"
-    local msg="$2"
-    if grep -qE "${pattern}" "${MOCK_LOG}" 2>/dev/null; then
-        printf '%b\n' "    ${GREEN}✓${NC} ${msg}"
-        PASSED=$((PASSED + 1))
-    else
-        printf '%b\n' "    ${RED}✗${NC} ${msg}"
-        FAILED=$((FAILED + 1))
-    fi
-}
-
-assert_agent_install() {
-    local cloud="$1"
-    local agent="$2"
-
-    case "$agent" in
-        claude)
-            # install_claude_code finalization always runs "claude install --force"
-            # (mock claude binary is pre-installed, so curl installer is skipped)
-            _assert_install_pattern "claude.*install" "installs claude code" ;;
-        openclaw)
-            # npm install -g openclaw (Node runtime needs standard node_modules layout)
-            _assert_install_pattern "npm.*install.*openclaw" "installs openclaw via npm" ;;
-        codex)
-            # npm install -g @openai/codex
-            _assert_install_pattern "npm.*install.*codex" "installs codex via npm" ;;
-        opencode)
-            # curl to download opencode tarball (via opencode_install_cmd)
-            _assert_install_pattern "opencode" "installs opencode" ;;
-        kilocode)
-            # npm install -g @kilocode/cli
-            _assert_install_pattern "npm.*install.*kilocode" "installs kilocode via npm" ;;
-        zeroclaw)
-            # curl installer from zeroclaw-labs/zeroclaw repo
-            _assert_install_pattern "zeroclaw" "installs zeroclaw" ;;
-        *)
-            # Unknown agent — skip assertion (no failure)
-            return 0 ;;
-    esac
-}

sh/test/fixtures/digitalocean/_api_assertions.sh

@@ -1,2 +0,0 @@
-assert_api_called "GET" "/account/keys" "fetches SSH keys"
-assert_api_called "POST" "/droplets" "creates droplet"

sh/test/fixtures/digitalocean/_env.sh

@@ -1,4 +0,0 @@
-export DO_API_TOKEN="test-token-do"
-export DO_DROPLET_NAME="test-srv"
-export DO_DROPLET_SIZE="s-2vcpu-2gb"
-export DO_REGION="nyc3"

sh/test/fixtures/hetzner/_api_assertions.sh

@@ -1,2 +0,0 @@
-assert_api_called "GET" "/ssh_keys" "fetches SSH keys"
-assert_api_called "POST" "/servers" "creates server"

sh/test/fixtures/hetzner/_env.sh

@@ -1,4 +0,0 @@
-export HCLOUD_TOKEN="test-token-hetzner"
-export HETZNER_SERVER_NAME="test-srv"
-export HETZNER_SERVER_TYPE="cx23"
-export HETZNER_LOCATION="fsn1"