[action-translation] resync: kalman_2.md (#119)

* 🔄 resync kalman_2.md

* Point references to untranslated lectures at the English site

These {doc} targets exist only in lecture-python.myst until Phase 2
translates them; qualifying with the intermediate: intersphinx prefix
gives working links now, and a future resync restores local refs once
the targets exist. Program decision recorded 2026-07-18 (Matt).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Restore CJKutf8 preamble and cjk() helper, add trailing newline

The resync kept upstream's text.usetex=True config but dropped the
zh-specific LaTeX adaptation (CJKutf8 package + the cjk() wrapper that
renders Chinese under usetex), while retaining the 13 cjk() call sites
in the plotting cells. Every figure cell raised NameError: name 'cjk'
is not defined. Restored the setup block from the current translation
(same i18n-adaptation class as the dropped font blocks in #107). Also
adds the missing trailing newline (QuantEcon/action-translation#116).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Add amsfonts to LaTeX preamble so \mathbb renders under usetex

The upstream rewrite introduced \mathbb{E}[...] notation in plot titles
and labels; the CJK-adapted preamble carried only CJKutf8+amsmath, so
under text.usetex=True the \mathbb control sequence was undefined and
fig.tight_layout() raised RuntimeError (latex failed). Upstream's own
preamble is amsmath,amsfonts; this restores amsfonts alongside the
zh-specific CJKutf8 adaptation.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: mmcky

.translate/state/kalman_2.md.yml

@@ -0,0 +1,6 @@
+source-sha: 7c6396a0a24cd9b944750681b42519179e6bab58
+synced-at: "2026-07-18"
+model: claude-sonnet-5
+mode: RESYNC
+section-count: 6
+tool-version: 0.17.0