feat: (Extension of #175) added cross-platform system-wide environment variable setup guide for all providers (#185)

* added Instructions to env example to allow openclaude to be used system wide

* added suggested .env.example changes

I added the suggested .env.example changes suggested earlier within the pr thread

.env.example

@@ -8,6 +8,120 @@
 # All other sections can be left commented out.
 # =============================================================================
 
+# =============================================================================
+# SYSTEM-WIDE SETUP (OPTIONAL)
+# =============================================================================
+# Instead of using a .env file per project, you can set these variables
+# system-wide so OpenClaude works from any directory on your machine.
+#
+# STEP 1: Pick your provider variables from the list below.
+# STEP 2: Set them using the method for your OS (see further down).
+#
+# ── Provider variables ───────────────────────────────────────────────
+#
+#   Option 1 — Anthropic:
+#     ANTHROPIC_API_KEY=sk-ant-your-key-here
+#     ANTHROPIC_MODEL=claude-sonnet-4-5              (optional)
+#     ANTHROPIC_BASE_URL=https://api.anthropic.com   (optional)
+#
+#   Option 2 — OpenAI:
+#     CLAUDE_CODE_USE_OPENAI=1
+#     OPENAI_API_KEY=sk-your-key-here
+#     OPENAI_MODEL=gpt-4o
+#     OPENAI_BASE_URL=https://api.openai.com/v1      (optional)
+#
+#   Option 3 — Google Gemini:
+#     CLAUDE_CODE_USE_GEMINI=1
+#     GEMINI_API_KEY=your-gemini-key-here
+#     GEMINI_MODEL=gemini-2.0-flash
+#     GEMINI_BASE_URL=https://generativelanguage.googleapis.com  (optional)
+#
+#   Option 4 — GitHub Models:
+#     CLAUDE_CODE_USE_GITHUB=1
+#     GITHUB_TOKEN=ghp_your-token-here
+#
+#   Option 5 — Ollama (local):
+#     CLAUDE_CODE_USE_OPENAI=1
+#     OPENAI_BASE_URL=http://localhost:11434/v1
+#     OPENAI_API_KEY=ollama
+#     OPENAI_MODEL=llama3.2
+#
+#   Option 6 — LM Studio (local):
+#     CLAUDE_CODE_USE_OPENAI=1
+#     OPENAI_BASE_URL=http://localhost:1234/v1
+#     OPENAI_MODEL=your-model-id-here
+#     OPENAI_API_KEY=lmstudio                        (optional)
+#
+#   Option 7 — AWS Bedrock (may also need: aws configure):
+#     CLAUDE_CODE_USE_BEDROCK=1
+#     AWS_REGION=us-east-1
+#     AWS_DEFAULT_REGION=us-east-1
+#     AWS_BEARER_TOKEN_BEDROCK=your-bearer-token-here
+#     ANTHROPIC_BEDROCK_BASE_URL=https://bedrock-runtime.us-east-1.amazonaws.com
+#
+#   Option 8 — Google Vertex AI:
+#     CLAUDE_CODE_USE_VERTEX=1
+#     ANTHROPIC_VERTEX_PROJECT_ID=your-gcp-project-id
+#     CLOUD_ML_REGION=us-east5
+#     GOOGLE_CLOUD_PROJECT=your-gcp-project-id
+#
+# ── How to set variables on each OS ──────────────────────────────────
+#
+# macOS (zsh):
+#   1. Open:  nano ~/.zshrc
+#   2. Add each variable as:  export VAR_NAME=value
+#   3. Save and reload:  source ~/.zshrc
+#
+# Linux (bash):
+#   1. Open:  nano ~/.bashrc
+#   2. Add each variable as:  export VAR_NAME=value
+#   3. Save and reload:  source ~/.bashrc
+#
+# Windows (PowerShell):
+#   Run for each variable:
+#     [System.Environment]::SetEnvironmentVariable('VAR_NAME', 'value', 'User')
+#   Then restart your terminal.
+#
+# Windows (Command Prompt):
+#   Run for each variable:
+#     setx VAR_NAME value
+#   Then restart your terminal.
+#
+# Windows (GUI):
+#   Settings > System > About > Advanced System Settings >
+#   Environment Variables > under "User variables" click New,
+#   then add each variable.
+#
+# ── Important notes ──────────────────────────────────────────────────
+#
+# LOCAL SERVERS: If using LM Studio or Ollama, the server MUST be
+# running with a model loaded before you launch OpenClaude —
+# otherwise you'll get connection errors.
+#
+# SWITCHING PROVIDERS: To temporarily switch, unset the relevant
+# variables in your current terminal session:
+#
+#   macOS / Linux:
+#     unset VAR_NAME
+#     # e.g.: unset CLAUDE_CODE_USE_OPENAI OPENAI_BASE_URL OPENAI_MODEL
+#
+#   Windows (PowerShell — current session only):
+#     Remove-Item Env:VAR_NAME
+#
+#   To permanently remove a variable on Windows:
+#     [System.Environment]::SetEnvironmentVariable('VAR_NAME', $null, 'User')
+#
+# LOAD ORDER:
+#   Shell and system environment variables are inherited by the process.
+#   Project .env files are only used if your launcher or shell loads them
+#   before starting OpenClaude.
+# COMPATIBILITY:
+#   System-wide variables work regardless of how you run OpenClaude:
+#   npx, global npm install, bun run, or node directly. Any process
+#   launched from your terminal inherits your shell's environment.
+#
+# REMINDER: Make sure .env is in your .gitignore to avoid committing secrets.
+# =============================================================================
 
 # =============================================================================
 # PROVIDER SELECTION — uncomment ONE block below
@@ -44,7 +158,7 @@ ANTHROPIC_API_KEY=sk-ant-your-key-here
 # GEMINI_MODEL=gemini-2.0-flash
 
 # Use a custom Gemini endpoint (optional)
-# GEMINI_BASE_URL=https://generativelanguage.googleapis.com
+# GEMINI_BASE_URL=https://generativelanguage.googleapis.com/v1beta/openai
 
 
 # -----------------------------------------------------------------------------
@@ -62,10 +176,39 @@ ANTHROPIC_API_KEY=sk-ant-your-key-here
 # OPENAI_API_KEY=ollama
 # OPENAI_MODEL=llama3.2
 
+# -----------------------------------------------------------------------------
+# Option 6: LM Studio (local models)
+# -----------------------------------------------------------------------------
+# LM Studio exposes an OpenAI-compatible API, so we use the OpenAI provider.
+# Make sure LM Studio is running with the Developer server enabled
+# (Developer tab > toggle server ON).
+#
+# Steps:
+#   1. Download and install LM Studio from https://lmstudio.ai
+#   2. Search for and download a model (e.g. any coding or instruct model)
+#   3. Load the model and start the Developer server
+#   4. Set OPENAI_MODEL to the model ID shown in LM Studio's Developer tab
+#
+# The default server URL is http://localhost:1234 — change the port below
+# if you've configured a different one in LM Studio.
+#
+# OPENAI_API_KEY is optional — LM Studio runs locally and ignores it.
+# Some clients require a non-empty value; if you get auth errors, set it
+# to any dummy value (e.g. "lmstudio").
+#
+# CLAUDE_CODE_USE_OPENAI=1
+# OPENAI_BASE_URL=http://localhost:1234/v1
+# OPENAI_MODEL=your-model-id-here
+
 
 # -----------------------------------------------------------------------------
-# Option 6: AWS Bedrock
+# Option 7: AWS Bedrock
 # -----------------------------------------------------------------------------
+
+# You may also need AWS CLI credentials configured (run: aws configure)
+# or have AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY set in your
+# environment in addition to the variables below.
+#
 # CLAUDE_CODE_USE_BEDROCK=1
 # AWS_REGION=us-east-1
 # AWS_DEFAULT_REGION=us-east-1
@@ -74,7 +217,7 @@ ANTHROPIC_API_KEY=sk-ant-your-key-here
 
 
 # -----------------------------------------------------------------------------
-# Option 7: Google Vertex AI
+# Option 8: Google Vertex AI
 # -----------------------------------------------------------------------------
 # CLAUDE_CODE_USE_VERTEX=1
 # ANTHROPIC_VERTEX_PROJECT_ID=your-gcp-project-id