Wiki badge and /wiki links in global search results (#14)

Theme half of the cross-repo wiki global search work (plugin half: sow-nodebb-plugin-wiki#12).

Search results tagged by the wiki plugin (`isWikiArticle` + `wikiPath`) now render with a gold "Wiki" badge and link to `/wiki/...` instead of `/post/...`:

- `templates/partials/quick-search-results.tpl` — navbar quick-search dropdown
- `templates/partials/search-results.tpl` — `/search` page, topics view
- `templates/partials/posts_list_item.tpl` — `/search` page, posts view (default). Shared with account/group post lists, where the wiki flags are never set and the conditional no-ops.
- `scss/westgate/_search.scss` — badge styling from existing `--wg-gold` / ledger-border tokens; imported from `theme.scss`
- `languages/en-GB/westgate.json` — `[[westgate:wiki-badge]]` label
- Spec updated with the resolved approach (template override, not client-side decoration)

Untagged forum results render byte-identical to Harmony stock.

Verification: all three overrides compiled and rendered against benchpressjs with mixed wiki/forum fixture rows (wiki row gets `/wiki/...` href + exactly one badge; forum rows keep stock `/post/...` links, `RE:` prefix and main-post icon preserved). New contract test in `tests/wiki-search-badge-contract.test.js`; suite passes except the pre-existing `global-footer-contract.test.js` failure (stale `join-the-team` link assertion from #10, also failing on main — not touched here).

End-to-end visual check (badge in the live dropdown + /search) still needs the dev stack with plugin PR #12 merged.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed-on: #14
Co-authored-by: vickydotbat <vickydotbat@tutamail.com>
Co-committed-by: vickydotbat <vickydotbat@tutamail.com>

theme.scss

@@ -7,6 +7,7 @@
 @import "./scss/westgate/categories";
 @import "./scss/westgate/topics";
 @import "./scss/westgate/posts";
+@import "./scss/westgate/search";
 @import "./scss/westgate/controls";
 @import "./scss/westgate/widgets";
 @import "./scss/westgate/responsive";