Fix nil pointer dereference in environment variable validation

[kofort9]

Description

Fixes a panic that occurs when running MCP servers with environment variables when no secrets manager is configured.

Related to #1469

The Problem

When running thv run <server> with environment variables in an environment without a configured secrets manager (e.g., GitHub Actions), the code panics with a nil pointer dereference at pkg/runner/env.go:117.

The Fix

Added a nil check before calling secretsManager.GetSecret() to gracefully handle the case where the secrets manager is not available.

Impact

Before: Panic when running MCP servers without secrets manager
After: Graceful handling - falls through to environment variables or prompts

This maintains backward compatibility:

• Users with secrets manager configured: Works as before
• Users without secrets manager: Now works correctly with environment variables

Testing

• Built and tested locally with environment variables
• No panic occurs
• go vet passes, gofmt compliant

[Copilot]

Pull Request Overview

This PR fixes a nil pointer dereference panic that occurs when running MCP servers with environment variables in environments where no secrets manager is configured (e.g., GitHub Actions).

Key Changes:

• Added nil check before accessing secretsManager.GetSecret() to prevent panic
• Gracefully falls through to environment variable prompts when secrets manager is unavailable

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 53.31%. Comparing base (bd12db9) to head (9f66c56).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/runner/env.go	0.00%	11 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2252      +/-   ##
==========================================
- Coverage   53.33%   53.31%   -0.02%     
==========================================
  Files         231      231              
  Lines       29529    29536       +7     
==========================================
- Hits        15749    15747       -2     
- Misses      12647    12656       +9     
  Partials     1133     1133              

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[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

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[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

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