Restore Realman arm specs and fix two #44 docs details

[timothy-weston]

Stacked on #44. This PR targets docs/dead-sharepoint-links, so merging it adds three commits to #44 and changes nothing else there.

Restore Realman's joint limits and weights (88236ba)

8a37e9a switched the WR65 and WRL63 tables to the specification tables in the manuals we publish. Realman's current parameters disagree with those tables, and the page values before 8a37e9a were Realman's:

	Realman (Gen 3 and Gen 4, English and Chinese)	Before 8a37e9a	8a37e9a
WR65 J1, J4	±178°	±178°	±180°
WR65 J5	±128°	±128°	±180°
WRL63 J1, J2, J4, J5	±178°	±178°	±180°
WRL63 J3	−178° to +145°	same	−150° to +165°
WRL63 weight (standard / force-sensing)	10 / 10.1 kg	10.0 / 10.1 kg	10.2 / 10.1 kg

Sources: Realman's RM65 and RML63 parameter pages, which give the same figures in the Gen 4 section, and the archived specifications restored in 6790cd8. The WR65 manual's own installation section also gives J5 as ±128°, and the WRL63 manual contains RM65 text.

• The joint tables are back to Realman's values. Each now names its source and the manual's differing values, so a customer comparing against the PDF knows which to plan to.
• Your 27 V supply maximum stays. It comes from the manuals, and the earlier 30 V was above the range the manual says can damage the arm.
• TODO.md: the J5 and weight items record this; the 10.1 kg force-sensing weight is sourced from Realman; the "raise with Realman" item lists both manuals' conflicts and asks which figures apply to the arms we have shipped.

check:downloads wording (e170ac0)

CONTRIBUTING.md said it fails when a <Downloads> query matches nothing. That holds only when the store's index is reachable. Otherwise it reports the queries as not checked and passes, by design (fetch_index() docstring). Wording only, no script change: a query that matches only retired documents also passes, and that is intended. The TODO item now covers just the "the build fails" wording in docs/design/file-hosting.md.

Upload skill preview step (d7fb1e6)

Step 7 said to delete static/_upload/ to preview the CI build, which loses any staged document not yet published. It now moves the folder outside the repository and back.

Checks

• npm run test:files: 48 tests pass
• npm run check:downloads: all 8 queries resolve
• npm run build: no warnings; the built WR65 and WRL63 pages show the restored tables