the README had drifted into being wrong; make it short and true

It still said Not built, listed pull and reachable — neither of which exists — and
claimed everything was decided in one round. Written at a conversion and never
touched again.

Deliberately does not enumerate the commands, because a prose command list is
exactly what went stale. It points at --help, which is the documentation surface we
already decided on and which cannot drift from the binary.

Worth noticing rather than logging: check catches documents that drift from their
publisher, and nothing catches ours drifting from our own code.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018UTxuSizozEA8yDitPuris

README.md

@@ -1,17 +1,18 @@
 # loom-cli
 
-**Not built.** *A small tool for the operations a person should not do by hand:
-fetch a document you depend on, and find out when it changed.*
+**`loomctl` fetches the documents this repository depends on, and tells you when
+they change.** It reports; it never repairs.
 
-**The design is in [`.loom/event-log.md`](.loom/event-log.md)**, *not in a spec.*
-**Every entry says what was decided and the belief that could turn out false**, so
-you can see which parts are load-bearing and which were guesses. *Everything
-tagged `osprey` was decided in one round.*
+```
+go build -o loomctl .
+./loomctl --help
+```
 
-**Three commands.** *`pull` adopts a document and writes its lock; `check` asks
-every publisher whether their copy has moved; `reachable` asks whether somebody
-who is not you can fetch what you published.* **None of them repairs anything.**
+`check` only reads. Nothing here writes over the network, so a credential it is
+given never needs write scope.
 
-**`bedrock` and `externals`, under [`.loom/externals/`](.loom/externals/), are not
-discardable.** *Read them as given — accommodating them is what makes this a loom
-tool rather than some other thing.*
+**Why it is the way it is:** [`.loom/event-log.md`](.loom/event-log.md). Every
+entry says what was decided and the belief that could turn out to be false.
+
+**What it depends on, and what we could not tell from those documents:**
+[`.loom/externals/`](.loom/externals/) — the `.gaps.md` files beside each one.