Rework /ctl into a self-describing dispatch table (name, desc, fn),
inspired by the ollie 9P server: an empty write or "help" lists the
verbs, and unknown verbs report the valid set.
New control verbs, each operating on a section subtree:
- rm: delete a section and its subtree
- move up|down: reorder among siblings
- promote/demote: shift the subtree's outline level
- refile <to-doc> [parent]: move a subtree across or within documents,
re-leveling to the target depth
- archive: move a subtree to the companion <doc>.org_archive file
- lint [doc]: reparse and report per document
Add a root /query file (rdwr): write a tag:X+todo:Y+priority:Z match
expression, read back matching sections.
Implement the previously stubbed agenda today/week views with real date
filtering, using a dependency-free civil-date day-number calculation.
Subtree edits share span-based helpers (subtree_range, sibling_ranges,
shift_headline_levels, insert_at). Covered by unit tests.
12869fb9f0