v0.2.2-alpha

Added

• Phase 6: string & formatting rework (spec §3/§18.1, v2.2). Python-style f-strings land: f"..."/f'...' with {expr} interpolation, {:spec} format refinements (float precision, zero-padding, width/alignment), {{/}} escapes, and raw rf"..."/rf'...' combined form. New literals: single-quoted strings '...' (escape-equivalent to "..."; a single character remains a Char per the spec BNF) and raw strings r"..."/r'...' (no escape processing). The lexer tracks {{/}} and brace/string nesting inside interpolations and rejects nested f-string literals as a compile-time error. Interpolations are rendered with the active print_format (default LaTeX).
• Doc comments (//////!) enter the AST (spec §4.1, v2.2). Doc comments are now language semantics: the lexer emits them, the parser collects consecutive lines into Program.module_docs/Import.docs/Stmt.*.docs/ClassMember.docs, and prima fmt re-emits them. A //////! with no following item warns W0007 unattached_doc_comment (spec §16.5; //! anywhere but the file top shares the code).
• Method-call diagnostic notes (spec §16.4, v2.2). When a method call fails — unknown method, wrong arity, visibility violation, or a runtime error thrown inside the method body — the diagnostic attaches a note with the method's signature, definition location, and /// doc, plus a did you mean suggestion for typos (String.toupper() → to_upper). prima check attaches the same definition note to stdlib @builtin call-site errors (E0050).
• prima doc Markdown output (spec §20). Renders # module title, //! module doc, and one ## section per definition with its /// doc and signature; -o FILE writes to a file and --stdlib documents every embedded stdlib module, giving offline method docs (spec §16.4).
• Stdlib & native-class doc comments (spec §4.1/§18.1/§18.4). Every embedded stdlib signature module (linalg, stats, io, num, plot, sys::path, sys::env, sys::os, time) carries a //! module doc and a /// doc per @builtin function, and a new embedded core::string module documents the native String class and its method set. At startup prima-stdlib parses string.pra and seeds the runtime doc registry (String class-level doc plus one String::<method> entry per member) with rendered signatures, /// doc text, and core/string.pra:<line>:<col> definition locations, so diagnostics attach a method signature + doc note to failed calls (spec §16.4).

Changed

• format removed (spec §18.1). It is no longer a pre-imported builtin; a call to a bare format(...) emits the transition warning W0006 (visible in prima check and evaluator warnings; --deny W0006 promotes it to an error) and then fails as an unknown function. Module functions such as time::format are unaffected. All examples/tests were migrated to f-strings (examples/fstring.pra is the new reference; examples/try_catch.pra now uses f-strings).
• Literal::Str renamed to Literal::String { value, quote, raw } (AST records the delimiter and raw-ness); prima fmt re-emits strings/f-strings losslessly and idempotently.