chore(repo): add git-cliff config, sort deps, add rust-version

- Add cliff.toml with GitHub remote wiring, issue link parsers, and
  clean group names (no sort prefixes)
- Add rust-version = "1.87.0" and codegen-units = 1 to workspace
- Sort workspace.dependencies alphabetically; add notstrap path entry
- Add CLAUDE.md preflight block; reformat workspace table to 100-col
- Delete stale brainstorm artifacts and root HANDOFF.md

crates/notsecrets/Cargo.toml

@@ -10,7 +10,6 @@ base64           = "0.22"
 bech32           = "0.11"
 chacha20poly1305 = "0.10"
 curve25519-dalek = "4"
-dirs             = { workspace = true }
 ed25519-dalek    = "2"
 hkdf             = "0.12"
 hmac             = "0.12"
@@ -24,7 +23,6 @@ thiserror        = { workspace = true }
 toml             = { workspace = true }
 x25519-dalek     = { version = "2", features = ["static_secrets"] }
 yubikey          = { version = "0.8", optional = true }
-zeroize          = "1"
 
 [features]
 default = []