Fix .NET version script and enhance Oh My Posh integration

[jmcombs]

Summary

This PR addresses the Oh My Posh integration feature requests and fixes a critical bug in the .NET version script that was causing Docker builds to fail.

Fixes #3 - Feature Request: Enhanced PowerShell Prompt with Oh My Posh Integration
Fixes #4 - Feature Request: Enhanced PowerShell Prompt with Oh My Posh Integration

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🐛 Bug Fix: .NET Version Script

Root Cause

The scripts/get-net-pwsh-versions.sh script was failing because Microsoft now has TWO active LTS .NET releases:

Version	Support Phase	Release Type	Latest Runtime
.NET 10.0	active	LTS	10.0.1
.NET 8.0	active	LTS	8.0.23

The script's jq query returned both results as a multi-line string, causing:

• latest_runtime = 10.0.1\n8.0.23 (multi-line)
• releases_json = URL1\nURL2 (multi-line)
• curl "$releases_json" fails with invalid URL
• All NET_RUNTIME_URL_* variables remain empty
• Docker build fails with "curl: (2) no URL specified"

Fix

Added first() to jq queries to select only the newest LTS release:

# Before (returns multiple results)
latest_runtime=$(echo "$response" | jq -r '.[] | select(...) | ...')

# After (returns only first/newest result)
latest_runtime=$(echo "$response" | jq -r 'first(.[] | select(...)) | ...')

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✨ Oh My Posh Enhancements

1. Embedded Blue PSL 10K Theme

• File: config/ohmyposh-container.json
• Custom theme based on Catppuccin Latte color palette
• Signature path_blue (#3465a4) color scheme
• Works offline without internet connection
• Two-line prompt with box-drawing characters
• Git integration with dynamic background colors

2. Runtime Environment Variables

• ENABLE_OHMYPOSH (default: true) - Disable Oh My Posh at runtime
• OHMYPOSH_THEME (default: empty) - Select custom themes

# Default - Blue PSL 10K theme (works offline)
docker run -it jmcombs/powershell

# Disable Oh My Posh entirely
docker run -it -e ENABLE_OHMYPOSH=false jmcombs/powershell

# Use built-in Oh My Posh theme
docker run -it -e OHMYPOSH_THEME=atomic jmcombs/powershell

# Use custom theme from URL
docker run -it -e OHMYPOSH_THEME=https://example.com/theme.omp.json jmcombs/powershell

3. Three-Tier Fallback Hierarchy

• Custom theme (from OHMYPOSH_THEME) → Blue PSL 10K (embedded) → Basic PowerShell prompt
• Prevents broken prompts if theme loading fails

4. Container Optimization

• Removed unused Nerd Font installation (~150MB savings)
• Fonts must be installed on HOST machine, not in container
• Fixed useradd shell from /bin/zsh to /bin/bash

5. Documentation Updates

• Added comprehensive host font configuration instructions
• Documented environment variables with usage examples
• Added theme fallback behavior explanation
• Added GitHub Sponsors badge

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📋 Files Changed

File	Changes
scripts/get-net-pwsh-versions.sh	Fixed jq queries with first()
config/ohmyposh-container.json	Replaced with Blue PSL 10K theme
config/Microsoft.PowerShell_profile.ps1	Theme selection logic and fallback
Dockerfile	Env vars, removed fonts, fixed shell
README.md	Host font docs, env vars, sponsors
scripts/test-ohmyposh-build.sh	Updated test script

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✅ Testing Results

Version Script

NET_RUNTIME_URL_arm=https://builds.dotnet.microsoft.com/dotnet/Runtime/10.0.1/dotnet-runtime-10.0.1-linux-arm.tar.gz
NET_RUNTIME_URL_arm64=https://builds.dotnet.microsoft.com/dotnet/Runtime/10.0.1/dotnet-runtime-10.0.1-linux-arm64.tar.gz
NET_RUNTIME_URL_x64=https://builds.dotnet.microsoft.com/dotnet/Runtime/10.0.1/dotnet-runtime-10.0.1-linux-x64.tar.gz

Docker Build

✅ Build completes successfully for linux/arm64

Container Tests

Test	Result
Container startup	✅ Pass
Oh My Posh installed	✅ Pass
Theme file exists	✅ Pass
ENABLE_OHMYPOSH default = true	✅ Pass
Profile loads Blue PSL 10K	✅ Pass
ENABLE_OHMYPOSH=false works	✅ Pass
OHMYPOSH_THEME=atomic works	✅ Pass
.NET 10.0.1 runtime installed	✅ Pass

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📝 Checklist

• Script fix tested locally
• Docker build completes
• All container tests pass
• Documentation updated
• Theme JSON is valid
• Environment variables work correctly
• Fallback mechanism tested

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Pull Request opened by Augment Code with guidance from the PR author