Fix #243/#252/#253: stop leaking settings posture to anonymous callers (#283)

Three settings endpoints were disclosing operational posture or
operator-curated configuration to any network caller. This change
either tightens the redacted-public view (#243) or adds a
local-operator auth gate (#252, #253) per the audit recommendations.

Zero hostility to legitimate users: in all three cases, the Tauri
shell (loopback), the Docker bridge frontend container (#250 + #278),
and any caller with an admin key continue to see the full data. Only
anonymous LAN/internet callers see the reduced surface.

== #243 (Wormhole transport posture, anonymous-mode, profile, node mode)

Tightened the public-redaction allowlists in BOTH the main.py and
routers/wormhole.py copies:
- _WORMHOLE_PUBLIC_SETTINGS_FIELDS: {enabled, transport, anonymous_mode}
                                 -> {enabled}
- _WORMHOLE_PUBLIC_PROFILE_FIELDS: {profile, wormhole_enabled}
                                 -> {wormhole_enabled}

`GET /api/settings/node` (both the routers/admin.py and main.py copies)
now returns an empty stub for unauthenticated callers and the full
node_mode + node_enabled fields only for authenticated callers via
_scoped_view_authenticated(request, "node").

== #252 (news feed inventory disclosure)

`GET /api/settings/news-feeds` now requires Depends(require_local_operator)
in both the canonical routers/admin.py handler and the duplicate main.py
handler. Anonymous callers can no longer enumerate operator-curated
feed names and URLs.

== #253 (Time Machine archival-capture posture disclosure)

`GET /api/settings/timemachine` now requires Depends(require_local_operator).
Anonymous callers can no longer fingerprint whether a deployment is
retaining replayable historical surveillance data.

Tests: backend/tests/test_round5_settings_info_disclosure.py (10 tests)
- Wormhole settings: anonymous sees only `enabled`; authenticated sees full state.
- Privacy profile: anonymous sees only `wormhole_enabled`; authenticated sees `profile` + `transport` + `anonymous_mode`.
- Node settings: anonymous sees `{}`; authenticated sees node_mode + node_enabled + persisted state.
- news-feeds: anonymous gets 403 (and get_feeds() is NOT called); authenticated gets full inventory.
- timemachine: anonymous gets 403; authenticated sees enabled + storage_warning.

Local: 73/73 security suite (round 5 + earlier rounds) green.

Credit: tg12 (external security audit, P1 + 2x Medium).

backend/main.py

@@ -1080,8 +1080,18 @@ def _public_mesh_log_size(entries: list[dict[str, Any]]) -> int:
     return sum(1 for item in entries if _public_mesh_log_entry(item) is not None)
 
 
-_WORMHOLE_PUBLIC_SETTINGS_FIELDS = {"enabled", "transport", "anonymous_mode"}
-_WORMHOLE_PUBLIC_PROFILE_FIELDS = {"profile", "wormhole_enabled"}
+# Issue #243 (tg12): the public redaction now exposes only the bare
+# "is Wormhole on?" boolean. Transport choice (tor/i2p/mixnet/direct),
+# anonymous-mode state, and the named privacy profile are all
+# operational posture and were leaking actionable recon to any
+# unauthenticated caller. They are now gated behind authenticated reads
+# (admin key or scoped-view token). Loopback Tauri shells and Docker
+# bridge frontend containers continue to see full status because the
+# Next.js catch-all proxy injects the configured ADMIN_KEY for
+# same-origin/non-browser callers (see PR #263), so legitimate operator
+# UX is unaffected.
+_WORMHOLE_PUBLIC_SETTINGS_FIELDS = {"enabled"}
+_WORMHOLE_PUBLIC_PROFILE_FIELDS = {"wormhole_enabled"}
 _PRIVATE_LANE_CONTROL_FIELDS = {"private_lane_tier", "private_lane_policy"}
 _PUBLIC_RNS_STATUS_FIELDS = {"enabled", "ready", "configured_peers", "active_peers"}
 _NODE_PUBLIC_EVENT_HOOK_REGISTERED = False
@@ -8810,9 +8820,14 @@ async def api_uw_flow(request: Request):
 from services.news_feed_config import get_feeds, save_feeds, reset_feeds
 
 
-@app.get("/api/settings/news-feeds")
+@app.get(
+    "/api/settings/news-feeds",
+    dependencies=[Depends(require_local_operator)],
+)
 @limiter.limit("30/minute")
 async def api_get_news_feeds(request: Request):
+    """Issue #252 (tg12): gated on local-operator. See the canonical
+    handler in backend/routers/admin.py for the full rationale."""
     return get_feeds()
 
 
@@ -9015,9 +9030,22 @@ class NodeSettingsUpdate(BaseModel):
 @app.get("/api/settings/node")
 @limiter.limit("30/minute")
 async def api_get_node_settings(request: Request):
+    """Issue #243 (tg12): node mode and participant state are
+    operational posture. Anonymous callers receive an empty stub —
+    enough for the UI to know the endpoint exists but nothing
+    fingerprintable. Authenticated callers see the full state.
+
+    Authenticated == local-operator (loopback / Docker bridge) OR an
+    admin / scoped-view token. The Tauri shell and Docker frontend
+    container both qualify via their existing transport (PR #263 +
+    PR #278), so legitimate operator UX is unchanged.
+    """
     from services.node_settings import read_node_settings
 
     data = await asyncio.to_thread(read_node_settings)
+    authenticated = _scoped_view_authenticated(request, "node")
+    if not authenticated:
+        return {}
     return {
         **data,
         "node_mode": _current_node_mode(),