Raise org-wide make test cap to 60s, backstop timeout to 90s

Per the ruling on prompts issue 41: the 60-second cap is org-wide, not a
per-repo divergence. 60 seconds is the hard cap for CI green; anything
over 20 seconds is still green but must be filed as an improvement bug.

The old pairing of a 20-second cap with a 30-second `-timeout` stays
coherent only if the backstop exceeds the cap, so the timeout moves to
90s (the same 1.5x ratio the old numbers had). Applied to the prose
ceiling in `REPO_POLICIES.md`, the Go example Makefile snippet, and the
`make test` lines in both repo checklists.

#41
sneak/dnswatcher#93

prompts/EXISTING_REPO_CHECKLIST.md

@@ -59,7 +59,9 @@ with your task.
 - [ ] README has an **Entrypoints** section documenting the `script/`
       entrypoints and linking the standard
 - [ ] `make check` does not modify any files in the repo
-- [ ] `make test` has a 30-second timeout
+- [ ] `make test` has a 90-second timeout and completes within the 60-second
+      hard cap (over 20 seconds is green but must be filed as an improvement
+      bug)
 - [ ] `make test` runs real tests, not a no-op (at minimum, import/compile
       check)
 - [ ] `make check` passes on current branch

prompts/NEW_REPO_CHECKLIST.md

@@ -80,8 +80,8 @@ are thin shims calling them. Model scripts:
       installs
 - [ ] `script/setup` / `make setup` — readies a fresh clone: runs `bootstrap`,
       then `install-precommit`, plus repo-specific init
-- [ ] `script/test` / `make test` — runs real tests, not a no-op (30-second
+- [ ] `script/test` / `make test` — runs real tests, not a no-op (90-second
-      timeout)
+      timeout, 60-second hard cap on wall time)
 - [ ] `script/lint` / `make lint` — runs linter
 - [ ] `script/fmt` / `make fmt` — formats code (writes)
 - [ ] `script/fmt-check` / `make fmt-check` — checks formatting (read-only)

prompts/REPO_POLICIES.md

@@ -189,8 +189,13 @@ style conventions are in separate documents:
   module under test to verify it compiles/parses. There is no excuse for
   `make test` to be a no-op.
 
-- `make test` must complete in under 20 seconds. Add a 30-second timeout in the
+- `make test` must complete in under 60 seconds. That is the hard cap, and a
-  Makefile.
+  suite that exceeds it fails. Under 20 seconds is the target. A suite between
+  20 and 60 seconds is still green, but the overage must be filed as an
+  improvement bug against that repo. Add a 90-second timeout to the test
+  invocation in the Makefile (`go test -timeout 90s`). The backstop deliberately
+  sits above the hard cap so that it catches a genuinely hung test rather than a
+  merely slow one.
 
 - **`make test` should use the conditional verbose rerun pattern.** Run tests
   without `-v` (verbose) first. If tests fail, automatically rerun with `-v` to
@@ -209,9 +214,9 @@ style conventions are in separate documents:
 
     ```makefile
     test:
-    	@go test -timeout 30s -race -cover ./... || \
+    	@go test -timeout 90s -race -cover ./... || \
     		{ echo "--- Rerunning with -v for details ---"; \
-    		  go test -timeout 30s -race -v ./...; exit 1; }
+    		  go test -timeout 90s -race -v ./...; exit 1; }
     ```
 
     Python example: