docs: restore D405/Gemini 305 design notes across README translations

[bowenszhu]

The D405/Gemini 305 mount design-notes links added in

• feat(hardware): replace D405/Gemini 305 wrist mount with validated design #69

were lost during subsequent README merges. This restores the links beside the existing STEP downloads in all 5 README languages, so readers can again find the matching source scripts, STL, validation data, and design rationale at the pinned v1.0.0 source repository.

The loss can be traced to two merge commits:

• First loss: 1bec06f (update tutorial link, 2026-09-02 02:52:34 UTC). Its first parent e325545 had no design-notes links, while its second parent 4ec35af had them. The merge result omitted them in all five languages. Compare the second parent with the merge result.
• Subsequent merge: 11f09f7 (2026-09-03 04:03:15 UTC). This merged the link-missing 1bec06f with eac3c45, which still contained the links, and again produced a result without them. Compare the link-containing parent with the merge result.

The later documentation restoration in

• docs: restore fixes lost in a conflicted merge, and make CI watch main itself #80

restored other README regressions but did not restore these design-notes links. These comparisons establish the content regression; they do not establish the exact conflict-resolution operation or intent.

Changes are limited to one table cell each in README.md, README_zh.md, README_Fr.md, README_JP.md, and README_es.md, using the original translated link labels. Existing STEP download paths and hardware assets are preserved.

Validation: reviewed the five-line diff and passed git diff --check. The current upstream STEP and installed-view image have the same Git blob hashes as the PR #69 merge 5dd1c00.

[bowenszhu]

The failing readme-sync check is caused by an existing translation mismatch on the base branch, rather than the design-notes links restored by this PR.

The failed job log reports that RS roadmap table 2 has 12 rows in README.md, but only 11 in README_zh.md, README_JP.md, and README_Fr.md. The missing row is Embodied Agent Architecture.

The row was added in all 5 languages by

• update #84

During the subsequent merge 00eccea (Merge branch 'main' into fix/restore-reverted-docs, part of

• docs: restore fixes lost in a conflicted merge, and make CI watch main itself #80

the English and Spanish rows were retained, while the Chinese, Japanese, and French rows were lost. The incoming parent b641ed0 contains all 5; this comparison shows the regression.

Restoring those 3 roadmap rows should resolve this failure. This PR only restores the design-notes links in the wrist-camera mount table and does not change the roadmap tables.

[Chirag6722]

The readme-sync failure here isn't from this PR — it's the one currently red on main:

README_zh.md: roadmap table 2 has 11 rows, README.md has 12
README_JP.md: roadmap table 2 has 11 rows, README.md has 12
README_Fr.md: roadmap table 2 has 11 rows, README.md has 12

Byte-for-byte the same three lines as the push run on main. Your #87 fixes exactly those three files and is green, so merging #87 first and then rebasing this should clear it — no change needed here.

link-check is already green on this branch.