Rewrite REPO_POLICIES.md sentence by sentence (closes #136)

Every sentence of prompts/REPO_POLICIES.md is rewritten against the
sentence rules: one idea per sentence, about 30 words at most, lists as
bulleted lists, subject and verb early, the main rule before any
exception. No rule's meaning changed: nothing is added, removed,
loosened or tightened, every reason stays, and code blocks, digests,
URLs, file names, commands and quoted strings are unchanged. Both repo
checklists carry the same rewrite of the sentences they quote word for
word.

Model: fable-5-1

TODO.md

@@ -21,6 +21,13 @@ fmt-check, and commit.
 
 # Completed Steps
 
+- 2026-11-03: Rewrote `prompts/REPO_POLICIES.md` sentence by sentence
+  (https://git.eeqj.de/sneak/prompts/issues/136), on sneak's yes at
+  https://git.eeqj.de/sneak/prompts/issues/136#issuecomment-165193. Every rule
+  keeps its meaning and its place, and `must` and `should` stay as they were.
+  Long sentences are split, comma-chained lists are now bulleted lists, and
+  every reason stays. Code blocks, digests, URLs, file names, commands and
+  quoted strings are unchanged.
 - 2026-11-03: A package from the distribution's own package index now needs no
   version and no hash, and pulling that index is allowed
   (https://git.eeqj.de/sneak/prompts/issues/72), on sneak's answer at