Bashou v0.12.0

Changes

• New lessons on SSH and firewalls, with two fights: the Key Kraken (fix the rights of ~/.ssh) and the Drop Dragon (find the nftables rule that drops a client).
• New lessons on Python errors and exit codes (the Except Eel), SQL's NULL (the Null Newt) and Rust ownership and borrowing (the Borrow Badger and the Vector Viper).
• The git lesson now covers conflicts, stash and undo, in seven pages, with the Revert Revenant.
• Every lesson ends on a quiz of its own questions, and three right answers open the lessons after it. 44 new questions, 488 in all.
• Boss questions give 25 to 40 seconds, more when the question and its choices take longer to read.
• The lesson library shows its two views as tabs under the title; f switches.
• The Stowaway Stoat is fought with dpkg and the Autoremove Adder with apt-mark, the commands their answers need.
• Lessons, questions and fights on Rust, C, git, networks, packages, CI/CD, logic, AI and Linux were reviewed against the official docs, man pages and release notes: Mac commands next to Linux ones, Debian 13's missing last, logs per system, EPEL with CRB, script injection that really injects, and many more.
• Several pets are lit from the top left, the Resolver Rook is redrawn as a chess tower, and the Snakelet and the Snake get the drawings they should have had in 0.11.0.
• The README opens on four pictures and the install.

Breaking changes

• Breaking change: a pony was given 40 seconds to answer a boss, spent 39 reading the choices and bolted at the last one. Bring it home with bashou pony hoof.