fix(analyzer): count grouped use-imports and bare module aliases

CRATE_RE only matched `crate::<mod>`, so it silently missed:
  * grouped imports `use crate::{id, session, tui};` (the char after
    crate:: is `{`, not an ident), and
  * every subsequent bare `tui::App` alias reference they enable.

This badly undercounted edge weights for any module pulled in via a
grouped use. e.g. cli->tui read as 6 refs when it is really ~25 (cli
launches tui::App), and video_export->tui (7 refs) was invisible
entirely. That mis-ranked the feedback-arc set and would have led to
'breaking' an edge that does not actually compile away.

Now parse `use crate::...;` statements per file, count grouped-import
edges that CRATE_RE cannot see, and attribute bare `alias::` usages to
the imported module (skipping the use lines themselves to avoid double
counting).