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/ui-conversation/src/client/skeleton/InputBar.module.css

@@ -225,9 +225,9 @@
      so by construction now that all three sit INSIDE .scroll — a scrollbar
      that consumes layout space narrows the scrollport, which is their shared
      containing block, so it costs all three the same width on every engine.
-     Scrolling the textarea itself is what used to break this, and no property
-     fixed it: WebKit reserved gutter space for the overflow-y:auto textarea
-     and not for the overflow:hidden layers beside it, leaving them 8px apart
+     A textarea that scrolls itself would break this, and no property fixes
+     it: WebKit reserves gutter space for an overflow-y:auto textarea and not
+     for the overflow:hidden layers beside it, leaving them 8px apart
      (768 against 776) — worth 2 to 5 wrapped lines on a long draft. */
 }