refactor: optimize token usage, deduplicate code, fix bugs across agents

Token reduction (~40% per session, ~2.3M fewer tokens per 200-feature project):
- Agent-type-specific tool lists: coding 9, testing 5, init 5 (was 19 for all)
- Right-sized max_turns: coding 300, testing 100 (was 1000 for all)
- Trimmed coding prompt template (~150 lines removed)
- Streamlined testing prompt with batch support
- YOLO mode now strips browser testing instructions from prompt
- Added Grep, WebFetch, WebSearch to expand project session

Performance improvements:
- Rate limit retries start at ~15s with jitter (was fixed 60s)
- Post-spawn delay reduced to 0.5s (was 2s)
- Orchestrator consolidated to 1 DB query per loop (was 5-7)
- Testing agents batch 3 features per session (was 1)
- Smart context compaction preserves critical state, discards noise

Bug fixes:
- Removed ghost feature_release_testing MCP tool (wasted tokens every test session)
- Forward all 9 Vertex AI env vars to chat sessions (was missing 3)
- Fix DetachedInstanceError risk in test batch ORM access
- Prevent duplicate testing of same features in parallel mode

Code deduplication:
- _get_project_path(): 9 copies -> 1 shared utility (project_helpers.py)
- validate_project_name(): 9 copies -> 2 variants in 1 file (validation.py)
- ROOT_DIR: 10 copies -> 1 definition (chat_constants.py)
- API_ENV_VARS: 4 copies -> 1 source of truth (env_constants.py)

Security hardening:
- Unified sensitive directory blocklist (14 dirs, was two divergent lists)
- Cached get_blocked_paths() for O(1) directory listing checks
- Terminal security warning when ALLOW_REMOTE=1 exposes WebSocket
- 20 new security tests for EXTRA_READ_PATHS blocking
- Extracted _validate_command_list() and _validate_pkill_processes() helpers

Type safety:
- 87 mypy errors -> 0 across 58 source files
- Installed types-PyYAML for proper yaml stub types
- Fixed SQLAlchemy Column[T] coercions across all routers

Dead code removed:
- 13 files deleted (~2,679 lines): unused UI components, debug logs, outdated docs
- 7 unused npm packages removed (Radix UI components with 0 imports)
- AgentAvatar.tsx reduced from 615 -> 119 lines (SVGs extracted to mascotData.tsx)

New CLI options:
- --testing-batch-size (1-5) for parallel mode test batching
- --testing-feature-ids for direct multi-feature testing

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

env_constants.py

@@ -0,0 +1,27 @@
+"""
+Shared Environment Variable Constants
+======================================
+
+Single source of truth for environment variables forwarded to Claude CLI
+subprocesses.  Imported by both ``client.py`` (agent sessions) and
+``server/services/chat_constants.py`` (chat sessions) to avoid maintaining
+duplicate lists.
+
+These allow autocoder to use alternative API endpoints (Ollama, GLM,
+Vertex AI) without affecting the user's global Claude Code settings.
+"""
+
+API_ENV_VARS: list[str] = [
+    # Core API configuration
+    "ANTHROPIC_BASE_URL",              # Custom API endpoint (e.g., https://api.z.ai/api/anthropic)
+    "ANTHROPIC_AUTH_TOKEN",            # API authentication token
+    "API_TIMEOUT_MS",                  # Request timeout in milliseconds
+    # Model tier overrides
+    "ANTHROPIC_DEFAULT_SONNET_MODEL",  # Model override for Sonnet
+    "ANTHROPIC_DEFAULT_OPUS_MODEL",    # Model override for Opus
+    "ANTHROPIC_DEFAULT_HAIKU_MODEL",   # Model override for Haiku
+    # Vertex AI configuration
+    "CLAUDE_CODE_USE_VERTEX",          # Enable Vertex AI mode (set to "1")
+    "CLOUD_ML_REGION",                 # GCP region (e.g., us-east5)
+    "ANTHROPIC_VERTEX_PROJECT_ID",     # GCP project ID
+]