New leaf crate op-util single-sources hex-color parsing (9 divergent
copies, one with a non-ASCII panic), JSON escaping (one copy was
lossy), and HTML/XML escaping (one copy missed the quote entity — an
attribute-injection gap). Desktop now delegates image generate/search,
settings payload serde, and the --mcp/--serve-web argv dispatch to
op-host-services / op-editor-host-core instead of carrying drifted
copies. Byte-identical widget_host twin files collapse into shared
op-editor-core host_ui_transitions. Auth routes, the MCP port, product
name, env-var names, service URLs, and status colors move to single
shared constants / theme tokens; the stale claude-sonnet-4-5 default
model id is corrected.
Relocate codegen.rs + codegen_targets.rs out of openpencil-shell-core
into a dedicated op-codegen crate. The code generators only depend on
jian-ops-schema + op-editor-core, so they form a clean leaf crate.
codegen.rs becomes the crate's lib.rs; crate::codegen:: paths in
codegen_targets.rs collapse to crate::. Pure relocation, no behaviour
change; tests move with their code.
