[rokso]

Fixes from two end-to-end reviews, and the 0.3.0 release (alpha dropped).

Fixed (also in 0.2.0):

• A CLI <old> address that is not an ERC-1967 or beacon proxy could pass as its own code; it now needs --old-implementation.
• Storage placed through a struct outside the namespaces (a library Layout) passed unchecked; it now stops with exit 2.
• solc ran in the caller's directory, so verified source could read a local file into an error; it now runs in an empty one.
• Explorer and verified-source text could spoof the terminal; it is now stripped, kept on one line, or refused.

Also: layoutFromSource removed, NamespaceCheck.result says unchecked, slotdiff keeps its own SAFETY_ERROR_KINDS, the publish job skips install scripts, and a weekly job tests against the newest OpenZeppelin 1.x. Breaking changes are listed in the CHANGELOG.