Add update.sh, release-channel tagging, mobile settings page

install.sh / install-nightly.sh:
  - Write .release-channel file ('release' or 'nightly') for future updates
  - install.sh also writes .release-version (for update --check)

update.sh (new):
  - Reads .release-channel to determine which channel to pull from
  - Release: checks releases/LATEST vs .release-version, skips if current
  - Nightly: always downloads latest
  - Stops service before extraction, restarts after
  - Rebuilds Python venv on update

ci/package.sh:
  - Include update.sh in distribution tarball

Web / mobile:
  - Add settings-page component for mobile
  - Wire settings page into mobile-app navigation
  - Chat page: load current user (/api/auth/me) for sender identity
  - Full mobile.css redesign
  - i18n: add mobile settings strings (en/fr/it)

ci/package.sh

@@ -17,7 +17,7 @@
 #
 # The tarball contains everything needed to run (or uninstall) Skald Circle:
 #   bin/skald, bin/skald-setup, web/, agents/, skills/,
-#   default.config.yaml, providers.yaml, requirements.txt, run.sh, uninstall.sh
+#   default.config.yaml, providers.yaml, requirements.txt, run.sh, update.sh, uninstall.sh
 
 set -eu
 
@@ -96,9 +96,9 @@ cp default.config.yaml "$STAGING/default.config.yaml"
 cp providers.yaml      "$STAGING/providers.yaml"
 cp requirements.txt    "$STAGING/requirements.txt"
 cp run.sh              "$STAGING/run.sh"
-cp uninstall.sh        "$STAGING/uninstall.sh"
-chmod 755 "$STAGING/run.sh" "$STAGING/uninstall.sh"
-
+cp update.sh            "$STAGING/update.sh"
+cp uninstall.sh         "$STAGING/uninstall.sh"
+chmod 755 "$STAGING/run.sh" "$STAGING/update.sh" "$STAGING/uninstall.sh"
 # ── Create tarball ────────────────────────────────────────────────────────────
 mkdir -p "$OUTPUT"
 TARBALL="$(cd "$OUTPUT" && pwd)/${PACKAGE_NAME}.tar.gz"