## 0. Pre-flight (non-negotiable)

- [ ] 0.1 Confirm clean working tree (`git status` reports nothing) and no in-flight worktrees with uncommitted work (`git worktree list` then `git status` in each)
- [ ] 0.2 If any worktrees exist under `.claude/worktrees/`, account for each one: still-active agent, work-pending-merge, or stale-and-prune. Stale worktrees MUST be removed (`git worktree remove`) before opening a new one — code that has been lost twice on main is the failure mode this guards against.
- [ ] 0.3 Confirm the package set in `MANIFEST.md` matches `find packages -maxdepth 3 -name package.json` count. Drift here means a prior change archived without regenerating the manifest.

## 1. drive-storage-archive-core (foundation)

- [x] 1.1 Scaffold `packages/drive/drive-storage-archive-core/` with `package.json`, vite/tsup config, vitest config via `createTestConfig()`, README, biome-clean tree
- [x] 1.2 Define `ArchiveFormat` union, `ArchiveMode`, `ArchiveCodec`, `ResolveSibling`, `PasswordHook`, `OpenArchiveStorageOptions` types in `src/types/`
- [x] 1.3 Implement `sniffFormat(bytes)` with magic-byte registry + structural validators (EOCD locate for zip, header checksum for tar, CRC trailer for gz, etc.)
- [x] 1.4 Implement `openArchiveStorage(source, opts)` factory with dynamic `import()` of per-format packages (no eager bundling)
- [x] 1.5 Implement `ARCHIVE_*` error code registry via `defineCodes` from `@suaveplan/error`
- [x] 1.6 Implement `runArchiveConformance(adapterFactory, opts)` harness exported via `./testing` subpath
- [x] 1.7 Implement default sibling-resolver helpers per format (`zipResolver`, `rarResolver`, `sevenZipResolver`) over a `DriveStorage`-shaped host
- [x] 1.8 Co-locate `.md` for every implementation file (Purpose, Features, Usage Basic/Advanced, API Reference, Implementation Notes — ≥200 words, real-import examples)
- [x] 1.9 100% Vitest coverage on `drive-storage-archive-core` via `bunx turbo test:coverage --filter=@suaveplan/drive-storage-archive-core`
- [x] 1.10 Green `bunx turbo lint typecheck test --filter=@suaveplan/drive-storage-archive-core`
- [x] 1.11 Update `MANIFEST.md` via `bun scripts/folder-reorg/generate-manifest.ts`

## 2. drive-storage-gz (foundation for tgz)

- [ ] 2.1 Scaffold `packages/drive/drive-storage-gz/`
- [ ] 2.2 Implement gzip member parser (RFC 1952), multi-member concatenation, FNAME extraction
- [ ] 2.3 Implement `GzipArchiveStorage` `DriveStorage` view with single-entry presentation
- [ ] 2.4 Implement `gzipCodec: ArchiveCodec` export for tgz composition
- [ ] 2.5 Implement write paths for `copy-on-write` and `rewrite` modes (full re-encode)
- [ ] 2.6 Implement CRC32 + ISIZE validation
- [ ] 2.7 Register `GZ_*` error codes
- [ ] 2.8 Run `runArchiveConformance` from `drive-storage-archive-core/testing`
- [ ] 2.9 Co-located `.md` docs per implementation file
- [ ] 2.10 100% coverage + lint + typecheck green
- [ ] 2.11 Regenerate MANIFEST

## 3. drive-storage-tar

- [ ] 3.1 Scaffold `packages/drive/drive-storage-tar/`
- [ ] 3.2 Implement tar block reader (512-byte alignment, two-block terminator)
- [ ] 3.3 Implement legacy v7, USTAR, POSIX.1-2001 PAX header parsing
- [ ] 3.4 Implement GNU long-name (`L`) and long-link (`K`) reconstruction
- [ ] 3.5 Implement PAX extended header records (path, size, mtime, atime, ctime, uid, gid)
- [ ] 3.6 Implement GNU sparse 1.0 reconstruction with zero-fill
- [ ] 3.7 Implement `TarArchiveStorage` `DriveStorage` view
- [ ] 3.8 Implement append-write fast path (before terminator) and full-rewrite path for deletes
- [ ] 3.9 Implement header-checksum validation, raise `TAR_HEADER_CHECKSUM_INVALID`
- [ ] 3.10 Register `TAR_*` error codes
- [ ] 3.11 Run `runArchiveConformance`
- [ ] 3.12 Co-located `.md` docs per implementation file
- [ ] 3.13 100% coverage + lint + typecheck green
- [ ] 3.14 Regenerate MANIFEST

## 4. drive-storage-tgz

- [ ] 4.1 Scaffold `packages/drive/drive-storage-tgz/`
- [ ] 4.2 Implement `TgzArchiveStorage` composing `TarArchiveStorage` over `ArchiveCodec`
- [ ] 4.3 Implement `openTarGz(source, opts)` convenience defaulting to `gzipCodec` from `drive-storage-gz`
- [ ] 4.4 Validate `ARCHIVE_CODEC_MISSING` on construction without codec
- [ ] 4.5 Implement write path (codec-encode tar bytes back to host)
- [ ] 4.6 Register `TGZ_*` error codes, propagate inner tar/codec errors with chain
- [ ] 4.7 Run `runArchiveConformance` with `gzipCodec`
- [ ] 4.8 Co-located `.md` docs per implementation file
- [ ] 4.9 100% coverage + lint + typecheck green
- [ ] 4.10 Regenerate MANIFEST

## 5. drive-storage-zip

- [x] 5.1 Scaffold `packages/drive/drive-storage-zip/`
- [x] 5.2 Implement EOCD + Central Directory parser, ZIP64 EOCD locator/record handling
- [x] 5.3 Implement Local File Header reader, deflate decode via `fflate`
- [x] 5.4 Implement WinZip AE-2 AES-256 decrypt with PBKDF2 key derivation
- [x] 5.5 Implement split-zip volume reassembly via `resolveSibling`, validate volume signatures
- [x] 5.6 Implement `ZipArchiveStorage` `DriveStorage` view
- [x] 5.7 Implement write path: append local headers + rebuild central directory + EOCD on flush
- [x] 5.8 Block AES write with `ZIP_AES_WRITE_UNSUPPORTED` (deferred to v0.2.0)
- [x] 5.9 Implement CRC32 validation, raise `ZIP_CRC_MISMATCH`
- [x] 5.10 Register `ZIP_*` error codes
- [x] 5.11 Run `runArchiveConformance`
- [x] 5.12 Co-located `.md` docs per implementation file
- [x] 5.13 100% coverage + lint + typecheck green
- [x] 5.14 Regenerate MANIFEST

## 6. drive-storage-7z

- [ ] 6.1 Scaffold `packages/drive/drive-storage-7z/`
- [ ] 6.2 Benchmark wasm LZMA vs `lzma-native` on 100MB archive; record decision in package README
- [ ] 6.3 Implement 7z trailing header parser, `EncodedHeader` decode path
- [ ] 6.4 Implement LZMA + LZMA2 decompression
- [ ] 6.5 Implement BCJ, BCJ2, Delta, ARM/X86/SPARC filter chain
- [ ] 6.6 Implement multi-volume reassembly (`.7z.NNN`) via `resolveSibling`
- [ ] 6.7 Implement `7zAES` header + content encryption with password hook
- [ ] 6.8 Implement `SevenZipArchiveStorage` `DriveStorage` view
- [ ] 6.9 Implement write path: re-encode affected folders + rewrite trailing header
- [ ] 6.10 Register `SEVENZ_*` error codes
- [ ] 6.11 Run `runArchiveConformance`
- [ ] 6.12 Co-located `.md` docs per implementation file
- [ ] 6.13 100% coverage + lint + typecheck green
- [ ] 6.14 Regenerate MANIFEST

## 7. drive-storage-rar (read-only, server-tier)

- [ ] 7.1 Scaffold `packages/drive/drive-storage-rar/` with `engines.node` + browser stub
- [ ] 7.2 Vendor wasm unrar (permissive license) or wire native binding; record license attribution in README
- [ ] 7.3 Implement RAR4 + RAR5 signature detection and version routing
- [ ] 7.4 Implement multi-volume reassembly: RAR5 `.partN.rar` + RAR4 `.r00`..`.r99` via `resolveSibling`
- [ ] 7.5 Implement encrypted-header and per-entry-encrypted reads with password hook
- [ ] 7.6 Implement `RarArchiveStorage` `DriveStorage` view; reject any non-`read-only` mode in constructor
- [ ] 7.7 Implement browser stub that throws `RAR_UNAVAILABLE_IN_BROWSER` for every entry point
- [ ] 7.8 Register `RAR_*` error codes
- [ ] 7.9 Run `runArchiveConformance` (read-only subset)
- [ ] 7.10 Co-located `.md` docs per implementation file
- [ ] 7.11 100% coverage + lint + typecheck green
- [ ] 7.12 Regenerate MANIFEST

## 8. Integration & cross-cutting

- [ ] 8.1 Wire `openArchiveStorage` end-to-end test fixture using a real `.zip`, `.tar`, `.gz`, `.tar.gz`, `.rar`, `.7z` and a split-zip set
- [ ] 8.2 Add an integration test demonstrating `new Drive(openArchiveStorage(...))` for each format
- [ ] 8.3 Update `openspec/specs/drive/spec.md` only if drive-side contract clarification is needed (likely no change — `DriveStorage` view already satisfied)
- [ ] 8.4 Run `bunx turbo lint typecheck test` across all seven new packages and ensure green
- [ ] 8.5 Run `bunx turbo test:coverage` across all seven packages and confirm 100% coverage on touched modules
- [ ] 8.6 Final `MANIFEST.md` regeneration + commit
- [ ] 8.7 Archive change to `openspec/archive/<yyyy-mm-dd>-add-drive-storage-archive/` per repo workflow