TypedPython: structured per-module 'why no C' report for pypackpack's native level #128

pypackpack #60 (compile slot) warns, at native, for every developer module that ships as bytecode, and needs a reason per module from TypedPython's pipeline.

Today compile_project returns ModuleResult.skipped: dict[name, str] with the line folded into the text ("line 30: ..."). Whether a module was not opted in at all, or was opted in but compiled nothing, can only be inferred from an empty dict.

Change:

• ModuleResult states the case: not_marked (no # typedpython: compiled and no @compiled), nothing_compiled, or compiled.
• Each skipped item is structured as name (function or class), package-relative file, line, and message. The line N: prefix moves out of the message.

Done when: tests cover the three cases and the structured items, and the CLI output (python -m typedpython build) shows file:line: name: message.