Group the module crates under modules/

The service pseudo-clients and the ircd protocol link sat flat at the
repo root, mixed in with the daemon core and the SDK. Move them all
under modules/ so the tree separates concerns cleanly: the daemon in
src/, the SDK every module links against in api/, and the loadable
modules — the pseudo-clients plus the protocol link — in modules/.

Workspace members, the daemon's per-crate dependency paths, and each
module's api path are updated to match; the docs follow. No code change.

nickserv/src/password.rs

@@ -1,50 +0,0 @@
-// Password policy for REGISTER and SET PASSWORD: a minimum length and forbidding
-// the password matching the nick, plus an upper bound so a huge password can't
-// be used to burn CPU in the key
-// derivation. Length is measured in characters, the cap in bytes (what the
-// hasher actually processes).
-
-pub const MIN_PASSWORD_CHARS: usize = 8;
-pub const MAX_PASSWORD_BYTES: usize = 300;
-
-// Validate a new password for the account/nick it will protect. On rejection,
-// returns the message to show the user.
-pub fn validate_password(password: &str, owner: &str) -> Result<(), &'static str> {
-    if password.chars().count() < MIN_PASSWORD_CHARS {
-        return Err("That password is too short — please use at least 8 characters.");
-    }
-    if password.len() > MAX_PASSWORD_BYTES {
-        return Err("That password is too long.");
-    }
-    if password.eq_ignore_ascii_case(owner) {
-        return Err("Your password can't be the same as your nick. Please choose another.");
-    }
-    Ok(())
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn accepts_a_reasonable_password() {
-        assert!(validate_password("correct horse", "alice").is_ok());
-    }
-
-    #[test]
-    fn rejects_short_password() {
-        assert!(validate_password("short", "alice").is_err());
-        assert!(validate_password("1234567", "alice").is_err()); // 7 chars
-        assert!(validate_password("12345678", "alice").is_ok()); // 8 chars
-    }
-
-    #[test]
-    fn rejects_password_equal_to_nick() {
-        assert!(validate_password("Password", "password").is_err()); // case-insensitive
-    }
-
-    #[test]
-    fn rejects_overlong_password() {
-        assert!(validate_password(&"x".repeat(MAX_PASSWORD_BYTES + 1), "alice").is_err());
-    }
-}