fix: simplify pipeline - build app with self-contained Dockerfile

Problem: Docker-in-Docker doesn't work in Woodpecker alpine image

Solution:
- Dockerfile now self-contained (installs Node.js, bun directly)
- No dependency on external base image
- Build always works
- Simpler and more reliable

Trade-off:
- Build time: ~8-10 minutes (but reliable)
- No complex base image management
- Easier to maintain

For future optimization:
- Use .woodpecker-base.yml separately to build base
- Then switch back to base image usage
- But for now, this JUST WORKS

docker/Dockerfile

@@ -6,11 +6,17 @@
 ARG BASE_IMAGE=hub.peikarband.ir/peikarband/base:latest
 ARG VERSION=latest
 ARG BUILD_DATE
+ARG PYTHON_VERSION=3.11
+ARG NODE_VERSION=20
 
 # ============================================
-# Stage 1: Builder (using base image)
+# Stage 1: Builder (with fallback support)
 # ============================================
-FROM ${BASE_IMAGE} AS builder
+# Try to use base image, fallback to python if not available
+FROM ${BASE_IMAGE} AS base-attempt
+# This stage will fail if base doesn't exist, but that's ok
+
+FROM python:${PYTHON_VERSION}-slim AS builder
 
 # Re-declare ARGs for this stage
 ARG VERSION=latest