Fix empty catch blocks — add handling or explanatory comments

[liliankasem]

Summary

There are at least 3 instances of empty or near-empty catch blocks that swallow exceptions without explanation. Per our coding standards, silently swallowing exceptions is only acceptable for genuine best-effort cleanup paths, and the catch block must include a comment explaining why losing the exception is acceptable.

Instances

1. src/Templates.DotNet/ItemTemplateHiveProvisioner.cs — empty catch
2. src/Templates.DotNet/DefaultDotnetTemplateRunner.cs — empty catch
3. src/Func/Quickstart/ManifestCache.cs — empty catch without explanatory comment

Proposed Fix

For each instance:

• If the catch is intentional (best-effort cleanup), add an explanatory comment per coding standards
• If the catch is hiding bugs, add proper error handling (log, rethrow, or wrap in domain exception)

Acceptance Criteria

• No empty catch blocks without explanatory comments
• Any catches that were hiding real errors are fixed with proper handling
• Build and tests pass