docs: add GitHub wiki + scripts/wiki.sh helper with secret-scan

Public docs now live at https://github.com/awizemann/scarf/wiki (separate
git repo cloned to .wiki-worktree/, mirroring the .gh-pages-worktree/
pattern). Internal dev notes stay in scarf/docs/.

scripts/wiki.sh wraps pull/commit/push with a two-pass secret-scan: hard
patterns (token regexes + private-key headers + a user-maintained
scripts/wiki-blocklist.txt) abort with non-zero exit; soft assignment
patterns (api_key=…, password=…, token=…) warn and require --force-terms.

CLAUDE.md gains a Wiki section listing the update triggers (new feature,
new service, architecture change, Hermes version bump, full release,
keyboard/sidebar change) and the workflow. CONTRIBUTING.md points
external contributors at the wiki Edit button or a direct clone.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -1,6 +1,7 @@
 # Xcode
 build/
 .gh-pages-worktree/
+.wiki-worktree/
 DerivedData/
 *.pbxuser
 !default.pbxuser
@@ -52,3 +53,6 @@ scarf/standards/backups/
 # history. RELEASE_NOTES.md stays tracked (committed with the version bump).
 releases/v*/*.zip
 releases/v*/appcast-entry.xml
+
+# Wiki helper: personal patterns (hostnames, IPs) blocked from the wiki push.
+scripts/wiki-blocklist.txt