refactor: optimization

[taygumus]

Refactor shell scripts, CLI containers & dev workflow

Summary

This PR focuses on cleanup and refactoring of shell scripts and development tooling, with the goal of improving readability, robustness, and developer experience without over-engineering.

The changes are mostly internal and do not alter production behavior.

---

Key changes

Shell scripts

• Standardized indentation to 2 spaces across all .sh files
• Clear separation between:
  • entrypoint / main scripts → set -e
  • utility / library functions → explicit return 0/1, no set -e
• Improved error handling:
  • return used consistently in functions
  • exit reserved for top-level scripts and signal handlers
  • errors printed to stderr where appropriate
• Simplified helpers to avoid unnecessary abstraction and eval where not needed
• More predictable control flow and clearer intent in all scripts

Docker / Compose (dev)

• CLI containers (wp-cli, db-cli) kept running in dev only to allow fast docker compose exec workflows
• Commands executed as secondary processes via exec, improving DX for common tasks
• Clarified dev vs prod intent (in prod these tasks should run via run --rm)
• Removed unnecessary complexity where Compose already provides correct behavior

Formatting & conventions

• Shell scripts: 2 spaces, no tabs
• YAML already aligned to 2 spaces
• Makefile and nginx configs left compliant with their own language rules
• Overall consistency across the codebase

---

Motivation

• Reduce cognitive load when reading shell scripts
• Avoid over-engineering and fragile abstractions
• Make dev workflows faster and more predictable
• Align scripts with common Docker and POSIX shell best practices

---

Scope

• Refactor only (no feature changes)
• No breaking changes expected
• Production behavior unchanged

---

Notes

This PR intentionally favors clarity and pragmatism over maximal abstraction.
Validation is done at entrypoints, while internal functions assume valid inputs and focus on execution.