Fold the August fleet findings into the policies, or drop them (closes #62)

Three findings from 2026-08-09 were rules a repository must follow that
`prompts/REPO_POLICIES.md` did not yet state, and are now added where a
reader would look: `golangci-lint config verify` is never run from
`make lint`, the lint phase or CI, since it fetches its schema over the
network; a new or changed check is proven by planting a defect it must
catch; and a workflow step that runs only on `main` is first run from
the feature branch. The issue records why every other finding was
dropped.

Model: opus-5-5

TODO.md

@@ -21,6 +21,13 @@ fmt-check, and commit.
 
 # Completed Steps
 
+- 2026-10-04: Went through the fleet findings recorded on 2026-08-09 (issue 62)
+  and added the three rules `REPO_POLICIES.md` did not yet state:
+  `golangci-lint config verify` is never run from `make lint`, the lint phase or
+  CI; a new or changed check is proven by planting a defect it must catch; and a
+  workflow step that runs only on `main` is first run from the feature branch.
+  The other findings were already stated, replaced by `--no-cache`, about git
+  worktrees, or about how agents work together; the issue gives each reason.
 - 2026-10-04: The note under the canonical Go `Dockerfile` example in
   `REPO_POLICIES.md` now installs lint-phase system libraries with `apt-get`
   under their Debian package names (issue 83). The `golangci/golangci-lint`