Remove all ctime from the codebase per sneak's decision on [PR #48](#48).
## Rationale
- ctime means different things on macOS (birth time) vs Linux (inode change time) — ambiguous cross-platform
- Vaultik never uses ctime operationally (scanning triggers on mtime change)
- Cannot be restored on either platform
- Write-only forensic data with no consumer
## Changes
- **Schema** (`internal/database/schema.sql`): Removed `ctime` column from `files` table
- **Model** (`internal/database/models.go`): Removed `CTime` field from `File` struct
- **Database layer** (`internal/database/files.go`): Removed ctime from all INSERT/SELECT queries, ON CONFLICT updates, and scan targets in both `scanFile` and `scanFileRows` helpers; updated `CreateBatch` accordingly
- **Scanner** (`internal/snapshot/scanner.go`): Removed `CTime: info.ModTime()` assignment in `checkFileInMemory()`
- **Tests**: Removed all `CTime` field assignments from 8 test files
- **Documentation**: Removed ctime references from `ARCHITECTURE.md` and `docs/DATAMODEL.md`
`docker build .` passes clean (lint, fmt-check, all tests).
closes#54
Co-authored-by: user <user@Mac.lan guest wan>
Reviewed-on: #55
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
Document the data model, type instantiation flow, and module
responsibilities. Covers chunker, packer, vaultik, cli, snapshot,
and database modules with detailed explanations of relationships
between File, Chunk, Blob, and Snapshot entities.
