Fix all 98 ruff lint errors across codebase

- Remove unused imports (app.py, stego_routes.py, killswitch.py, etc.)
- Sort import blocks (I001)
- Add missing os import in stego_routes.py (F821)
- Rename shadowed Click commands to avoid F811 (status→chain_status, show→chain_show)
- Rename uppercase locals R→earth_r, _HAS_QRCODE_READ→_has_qrcode_read (N806)
- Suppress false-positive F821 for get_username (closure scope)
- Use datetime.UTC alias (UP017)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontends/web/blueprints/attest.py

@@ -13,9 +13,8 @@ import json
 import socket
 from datetime import UTC, datetime
 
-from flask import Blueprint, Response, flash, redirect, render_template, request, url_for
-
 from auth import login_required
+from flask import Blueprint, Response, flash, redirect, render_template, request, url_for
 
 bp = Blueprint("attest", __name__)
 
@@ -23,6 +22,7 @@ bp = Blueprint("attest", __name__)
 def _get_storage():
     """Get verisoo LocalStorage pointed at soosef's attestation directory."""
     from verisoo.storage import LocalStorage
+
     from soosef.paths import ATTESTATIONS_DIR
 
     return LocalStorage(base_path=ATTESTATIONS_DIR)
@@ -31,6 +31,7 @@ def _get_storage():
 def _get_private_key():
     """Load the Ed25519 private key from soosef identity directory."""
     from verisoo.crypto import load_private_key
+
     from soosef.paths import IDENTITY_PRIVATE_KEY
 
     if not IDENTITY_PRIVATE_KEY.exists():
@@ -165,8 +166,8 @@ def attest():
                 )
 
             # Save our own identity so we can look it up during verification
-            from verisoo.models import Identity
             from cryptography.hazmat.primitives.serialization import Encoding, PublicFormat
+            from verisoo.models import Identity
 
             pub_key = private_key.public_key()
             pub_bytes = pub_key.public_bytes(Encoding.Raw, PublicFormat.Raw)

frontends/web/blueprints/fieldkit.py

@@ -2,9 +2,9 @@
 Fieldkit blueprint — killswitch, dead man's switch, status dashboard.
 """
 
+from auth import admin_required, get_username, login_required
 from flask import Blueprint, flash, redirect, render_template, request, url_for
 
-from auth import admin_required, get_username, login_required
 from soosef.audit import log_action
 
 bp = Blueprint("fieldkit", __name__, url_prefix="/fieldkit")

frontends/web/blueprints/keys.py

@@ -2,9 +2,9 @@
 Key management blueprint — unified view of all key material.
 """
 
-from flask import Blueprint, flash, redirect, render_template, request, url_for
-
 from auth import get_username, login_required
+from flask import Blueprint, flash, redirect, render_template, url_for
+
 from soosef.audit import log_action
 
 bp = Blueprint("keys", __name__, url_prefix="/keys")