docs: fix round-3 review findings — §/used-to/v1 residuals, zh stamp example, budget freeze honored

Delete the three §-citation residuals (web-app cordis.patch.yml, two
client design.md §-headers); recast the two CSS used-to narrations and
hmr's four v1 labels as current-state prose; narrow the zh exemption
example to 'this cut' (「本版本」 legitimately renders 'This version');
extend the candidate gate list with the post-battery shapes (§\d with a
committed-owner carve-out, 'used to', bare v1) on both sides and
re-record; honor the over-target ceiling freeze — docs/AGENTS.md
condensed to 1320 and the ceiling restored to 1320.

packages/client/runtime/tests/slots-service.spec.ts

@@ -1,5 +1,5 @@
 /**
- * SlotsService terminal-design account (design.md §11-3 main landing):
+ * SlotsService terminal-design account:
  * built-in 'root', the three load-time throws (duplicate declaration /
  * undeclared contribution / cross-scope store handle), the renderer installation
  * contract (double install / not installed / non-root key), store instance