refactor(org-config): surface narrowing + sparse-tree under C-; O

Narrowing and sparse-tree commands existed in the `:bind' block
on `C-c'-style shortcuts but nothing in `cj/org-map' surfaced
them, so which-key never showed them and discoverability was
poor.

Add direct bindings under `C-; O', flat (no sub-prefixes for
narrow / sparse-tree).  Lowercase creates; capital of the same
letter cancels:

- `n' / `N'  narrow-to-subtree / widen
- `s' / `S'  match-sparse-tree / show-all
- `t' / `T'  show-todo-tree / show-all
- `>' / `<'  forward / backward sibling narrow (kept as-is)
- `R'        reveal-context (no lowercase pair -- `r' is the
             table-row sub-prefix)

Both `S' and `T' resolve to the same `org-show-all' command so
the mental model is just "capital cancels the lowercase I just
ran" without having to recall which letter the cancel actually
lives on.

Free up F2: the old `(<f2> . org-reveal)' binding in the org-mode
`:bind' block is now redundant with `C-; O R'.  Drop it; F2
becomes available for whatever wants it next.

Four new ERT assertions in `test-org-config-keymap-ownership.el'
lock the shape -- the old sparse-tree-submap test was rewritten
for the flat layout and the narrow-submap test became
narrow-bindings (also flat).

0 files changed, 0 insertions, 0 deletions