Add CI workflows, linting configuration, and code quality improvements

[corylanou]

Summary

This PR adds comprehensive CI/CD infrastructure, linting configuration, and various code quality improvements to the LTX project.

Changes Made

CI/CD Infrastructure

• Added GitHub Actions workflows:
  • test-and-lint.yml: Runs tests across Go 1.22, 1.23, 1.24, executes linters (go fmt, go vet, staticcheck, revive), and builds the project
  • race-detection.yml: Prepared for future race condition testing (currently disabled)
• Added .revive.toml: Comprehensive linting configuration with appropriate rules for the project

Code Quality Improvements

• Fixed all linter warnings across the codebase:
  • Added missing package documentation comments
  • Fixed receiver naming consistency
  • Removed unused parameters and return values
  • Improved error handling patterns
  • Fixed variable naming (e.g., SQLITE_DATABASE_HEADER_STRING → sqliteDatabaseHeaderString)
  • Added missing JSON marshaling documentation
  • Fixed type assertion safety checks
  • Replaced deprecated math/rand.Read with crypto/rand.Read in tests
  • Renamed variables to avoid shadowing built-in functions (min/max → minTXID/maxTXID)

Documentation Updates

• Enhanced README.md:
  • Improved formatting with proper markdown headers
  • Added detailed checksum design documentation explaining database vs file checksums
  • Clarified security considerations for page index inclusion in file checksums
  • Fixed header layout table to show accurate field offsets and sizes

Build Configuration

• Updated .gitignore: Added Go binary exclusions (cmd/ltx/ltx, ltx)

File Changes Summary

• CI/CD: Added 2 new GitHub Actions workflows (123 lines)
• Linting: Added .revive.toml configuration (56 lines)
• Code fixes: Updated 16 Go files to address linter warnings (including test files)
• Documentation: Enhanced README with checksum design section

Test Plan

• All tests pass across Go 1.22, 1.23, 1.24
• No linting issues (go fmt, go vet, staticcheck, revive)
• Builds successfully

🤖 Generated with Claude Code

[corylanou]

Assessed this while clearing the backlog. The tooling in here is worth having, but the PR as a whole has gone stale enough that rebasing it is probably the wrong move.

Every core file it touches was rewritten last week.

File	Last changed on main
checksum.go	#89 — exclude lock page, close files
cmd/ltx/apply.go	#91 — honor checksum-free files
cmd/ltx/encode_db.go	#90 — write valid snapshots safely
ltx.go	#92 — format documentation
README.md	#92 — format documentation

This branch dates from Aug 2025 and its code changes predate all of that, plus the LZ4 block-format switch in #73. GitHub already reports it CONFLICTING/DIRTY. Reconciling 18 files of year-old changes against work that just landed is a lot of risk for changes whose value has largely been overtaken.

The CI and lint config is the part still worth taking, and it's cleanly separable — .github/workflows/test-and-lint.yml, .github/workflows/race-detection.yml, and .revive.toml are all new files with no conflicts. That's also the highest-value part: #81 and #82 shipped broken through three releases precisely because there were no tests under cmd/ltx and no lint gate. Those exist now, but nothing enforces coverage of new commands.

Suggested split: open a fresh PR carrying just the workflow files and .revive.toml, and close this one. That gets the tooling in within a day instead of a rebase slog, and lets the code changes be re-evaluated on their own merits against current main rather than smuggled in behind a CI change.

Two things to fix in the config before it lands.

The Go matrix here is ['1.22', '1.23', '1.24']. #78 raises the module floor to 1.26 because crypto/hpke does not exist before then, so that matrix and #78 cannot both be right. Even without #78, main is on 1.24 today, so testing 1.22 and 1.23 tests configurations the module already declares unsupported.

The .gitignore addition covers cmd/ltx/ltx and ltx but not dist/, which is the one that actually bites — see #93. dist/ltx is a committed binary and dist/ is where both the documented release build and the E2E script write, so it gets dirtied routinely. Worth folding that in.