Qualify “source” as convention source or module source

The unqualified term “source” refers both to reusable convention providers and to TypeScript import/export module specifiers, with additional generic source identifiers in the parser. This makes types, variables, messages, and documentation ambiguous.

Relevant files:

• packages/konsistent/src/config/source-resolver.ts
• packages/konsistent/src/config/reference-expander.ts
• packages/konsistent/src/typescript/types.ts
• packages/konsistent/src/typescript/predicates/import-source.ts
• docs/reference/reusable-conventions.md

Use the fully qualified terms “convention source” and “module source” throughout code and prose, including identifiers such as conventionSourceMap and moduleSource. Avoid bare source wherever either domain meaning is possible.

Backward compatibility: internal names and documentation can be renamed or removed without compatibility shims. No konsistent.json schema change is required; if a schema-facing field is renamed, retain the old name and behavior as deprecated and emit a non-failing CLI warning when it is used.

Start by searching the five listed files and the surrounding TypeScript and documentation for ambiguous uses of “source.” Trace configuration and schema-facing names before renaming identifiers, then verify that internal terms distinguish convention sources from module sources and that any renamed schema-facing field keeps deprecated behavior with a non-failing CLI warning.