What type of PR is this?

• feat (new feature)
• fix (bug fix)
• docs (documentation)
• style (formatting, no code change)
• refactor (code change that neither fixes a bug nor adds a feature)
• perf (performance improvement)
• test (adding or updating tests)
• chore (maintenance, tooling)
• build / ci (build or CI changes)

Which issue(s) this PR fixes

Fixes #6 #5

What this PR does / why we need it

Bug Fixes

• Fix branch operations (checkout, delete, merge, diff) not sanitizing hyphenated names
• Fix FakeBackend.purge() missing memory_ids parameter
• Fix cloud memory_purge only supporting single ID deletion

Input Validation

• Add memory_type validation in memory_store
• Add empty content check in memory_store
• Clamp top_k to [1, 100] in retrieve/search, [1, 200] in checkout, [1, 500] in diff
• Validate branch/snapshot names (non-empty, ≤100 chars)
• Validate rebuild_index table name
• Validate merge strategy value

CI/CD Improvements

• Merge lint and type-check into single job
• Move e2e env to job level (eliminate duplication)
• Remove redundant unit job (make test runs full suite)
• Add integration tests to CI
• Add make format command
• Rename workflows to lowercase (test, lint, publish, pr-title)
• Add unit test gate before PyPI publish