Fixes for M-02 to M-14, G-01 to G-14, K-02 to K-04, X-04 to X-14, not yet reviewed

Committed before review so Windows and WSL builds can start.
Each fix was tested and mutation-checked here; the codex review
of each item is still to come, so tasks/BUGS.md stays unticked.

M-02 is mid-review: round 1 findings are fixed (apps/ely-mark/src/tally.rs).
K-01 stays deferred. The ElyMark window test mark-outside.sh failed
once at its crash-recovery step in the last run; not yet looked into.

apps/ely-tree/src/pick.rs

@@ -45,6 +45,8 @@ impl Tree {
     /// Shows `path` as listed in `section`.
     pub fn show(&mut self, path: &str, section: ChangeSection, cx: &mut Context<Self>) {
         let Some(repo) = self.active else { return };
+        // A new pick leaves any file history or blame.
+        self.look = None;
         self.shown = Some(Shown {
             repo,
             section,