feat(miner): add .cs to READABLE_EXTENSIONS for C# project support

[mgattilabs]

feat(miner): add .cs to READABLE_EXTENSIONS for C# project support

Summary

Adds .cs (C#) to the READABLE_EXTENSIONS set in miner.py so that C# source
files are picked up and indexed when mining a .NET / C# project.

Motivation

Users working on C# codebases were finding that their source files were silently
skipped during mempalace mine because .cs was absent from the readable-
extensions allow-list. This change brings C# to parity with the other supported
languages (Python, JavaScript, TypeScript, Go, Rust, etc.).

Changes

File	Change
mempalace/miner.py	Added ".cs" to READABLE_EXTENSIONS
tests/test_miner.py	Added test_scan_project_picks_up_cs_files to verify the extension is scanned

Diff

# mempalace/miner.py
 READABLE_EXTENSIONS = {
     ...
     ".csv",
     ".sql",
     ".toml",
+    ".cs"
 }

Testing

# Run the full miner test suite (all 32 tests must pass)
python -m pytest tests/test_miner.py -v

All 32 tests pass, including the new test_scan_project_picks_up_cs_files test.

Checklist

• Feature branch: feat/miner-add-cs-extension → target develop
• Code follows project style (ruff, snake_case, no new dependencies)
• New test added (test_scan_project_picks_up_cs_files)
• All existing tests pass (32 passed)
• No API keys or external services required
• Verbatim storage unaffected — change is index-layer only (which files get picked up)
• Conventional commit message used: feat(miner): add .cs to READABLE_EXTENSIONS for C# project support

PR Target

Base branch: develop
Head branch: feat/miner-add-cs-extension