docs: bring the README layout and the branch claim back to the code

README described a three-skill plugin that ships six. skills/page and
skills/wiki were absent from What it ships and from the project tree, so
/tea:page and /tea:wiki could not be discovered from the front page at
all; labels.py, close.py, evict.py, issue_evict.py, pin.py and the
agents-sync hook were missing from the tree too. Layout now matches
AGENTS.md, and says which of the two is authoritative.

The sync skill promised that push writes the computed branch back into
the issue file. It cannot: a successful push deletes the file, which
push.py:260-271 and its docstring already said. The paragraph now says
what happens instead — the ref goes up, and the branch comes back on the
next pull, from the tracker. The three claims around it were correct and
are kept.

Closes #27
Closes #31

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

skills/sync/SKILL.md

@@ -355,8 +355,11 @@ A milestone must already exist in the repo — push attaches, it does not create
 
 `branch:` is Gitea's `ref`, the branch the work actually lives on. Push fills
 an empty one with the current git branch (`git rev-parse --abbrev-ref HEAD`)
-and writes it back into the issue file; a value already there is never
-overwritten, neither on create nor on `--update`. On a detached HEAD or outside
+and sends it up as `ref`; a value already there is never
+overwritten, neither on create nor on `--update`. Nothing is written back to
+the issue file — there is no file left to write to, because a successful push
+deletes it. The branch comes back on disk with the next `pull.py <n>`, from
+the tracker. On a detached HEAD or outside
 a git repo no `ref` is sent and a warning names the issues that went up without
 one. Reading the branch is the only thing these scripts ask git for — they
 never check out, create, or write anything.