feat(notfiles): hexagonal architecture refactor with adapters, integration tests, and notsecrets cleanup

- Extract FileStore port and InMemoryFileStore/FileStoreImpl/Reporter adapters
- Add Reporter trait to notcore with TerminalReporter and JsonReporter
- Refactor linker, package, status modules to use FileStore port
- Add integration test suite with dotfiles fixtures
- Add cross-crate integration tests
- Remove ssh_rsa identity/recipient (unsupported)
- Add rustqual.toml, .sccignore, notfiles.toml config files
- Update CLAUDE.md, README.md, AGENTS.md with current architecture

crates/notsecrets/Cargo.toml

@@ -14,7 +14,6 @@ serde            = { workspace = true }
 toml             = { workspace = true }
 x25519-dalek     = { version = "2", features = ["static_secrets"] }
 ed25519-dalek    = "2"
-rsa              = { version = "0.9", features = ["sha2"] }
 sha2             = "0.10"
 hkdf             = "0.12"
 chacha20poly1305 = "0.10"