Implement 14 power-user feature requests for field deployment

Critical:
- FR-01: Chain verification now supports key rotation via signed rotation
  records (soosef/key-rotation-v1 content type). Old single-signer
  invariant replaced with authorized-signers set.
- FR-02: Carrier images stripped of EXIF metadata by default before
  steganographic encoding (strip_metadata=True). Prevents source
  location/device leakage.

High priority:
- FR-03: Session timeout (default 15min) + secure cookie flags
  (HttpOnly, SameSite=Strict, Secure when HTTPS)
- FR-04: CSRF protection via Flask-WTF on all POST forms. Killswitch
  now requires password re-authentication.
- FR-05: Collaborator trust store — trust_key(), get_trusted_keys(),
  resolve_attestor_name(), untrust_key() in KeystoreManager.
- FR-06: Production WSGI server (Waitress) by default, Flask dev
  server only with --debug flag.
- FR-07: Dead man's switch sends warning during grace period via
  local file + optional webhook before auto-purge.

Medium:
- FR-08: Geofence get_current_location() via gpsd for --here support.
- FR-09: Batch attestation endpoint (/attest/batch) with SHA-256
  dedup and per-file status reporting.
- FR-10: Key backup tracking with last_backup_info() and
  is_backup_overdue() + backup_reminder_days config.
- FR-11: Verification receipts signed with instance Ed25519 key
  (schema_version bumped to 2).
- FR-12: Login rate limiting with configurable lockout (5 attempts,
  15 min default).

Nice-to-have:
- FR-13: Unified `soosef status` pre-flight command showing identity,
  channel key, deadman, geofence, chain, and backup status.
- FR-14: `soosef chain export` produces ZIP with JSON manifest,
  public key, and raw chain.bin for legal discovery.

Tests: 157 passed, 1 skipped, 1 pre-existing flaky test.

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

frontends/web/blueprints/attest.py

@@ -9,6 +9,7 @@ Wraps verisoo's attestation and verification libraries to provide:
 
 from __future__ import annotations
 
+import hashlib
 import json
 import socket
 from datetime import UTC, datetime
@@ -209,6 +210,79 @@ def attest():
     return render_template("attest/attest.html", has_identity=has_identity)
 
 
+@bp.route("/attest/batch", methods=["POST"])
+@login_required
+def attest_batch():
+    """Batch attestation — accepts multiple image files.
+
+    Returns JSON with results for each file (success/skip/error).
+    Skips images already attested (by SHA-256 match).
+    """
+    import hashlib
+
+    from soosef.verisoo.hashing import hash_image
+
+    private_key = _get_private_key()
+    if private_key is None:
+        return {"error": "No identity key. Run soosef init first."}, 400
+
+    files = request.files.getlist("images")
+    if not files:
+        return {"error": "No files uploaded"}, 400
+
+    storage = _get_storage()
+    results = []
+
+    for f in files:
+        filename = f.filename or "unknown"
+        try:
+            image_data = f.read()
+            sha256 = hashlib.sha256(image_data).hexdigest()
+
+            # Skip already-attested images
+            existing = storage.get_records_by_image_sha256(sha256)
+            if existing:
+                results.append({"file": filename, "status": "skipped", "reason": "already attested"})
+                continue
+
+            from soosef.verisoo.attestation import create_attestation
+
+            attestation = create_attestation(image_data, private_key)
+            index = storage.append_record(attestation.record)
+
+            # Wrap in chain if enabled
+            chain_index = None
+            config = request.app.config.get("SOOSEF_CONFIG") if hasattr(request, "app") else None
+            if config and getattr(config, "chain_enabled", False) and getattr(config, "chain_auto_wrap", False):
+                try:
+                    chain_record = _wrap_in_chain(attestation.record, private_key, {})
+                    chain_index = chain_record.chain_index
+                except Exception:
+                    pass
+
+            results.append({
+                "file": filename,
+                "status": "attested",
+                "record_id": attestation.record.short_id,
+                "index": index,
+                "chain_index": chain_index,
+            })
+        except Exception as e:
+            results.append({"file": filename, "status": "error", "error": str(e)})
+
+    attested = sum(1 for r in results if r["status"] == "attested")
+    skipped = sum(1 for r in results if r["status"] == "skipped")
+    errors = sum(1 for r in results if r["status"] == "error")
+
+    return {
+        "total": len(results),
+        "attested": attested,
+        "skipped": skipped,
+        "errors": errors,
+        "results": results,
+    }
+
+
 def _verify_image(image_data: bytes) -> dict:
     """Run the full verification pipeline against the attestation log.
 
@@ -389,7 +463,7 @@ def verify_receipt():
         matching_records.append(rec_entry)
 
     receipt = {
-        "schema_version": "1",
+        "schema_version": "2",
         "verification_timestamp": verification_ts,
         "verifier_instance": verifier_instance,
         "queried_filename": image_file.filename,
@@ -403,6 +477,19 @@ def verify_receipt():
         "matching_records": matching_records,
     }
 
+    # Sign the receipt with the instance's Ed25519 identity key
+    private_key = _get_private_key()
+    if private_key is not None:
+        from cryptography.hazmat.primitives.serialization import Encoding, PublicFormat
+
+        pub_bytes = private_key.public_key().public_bytes(Encoding.Raw, PublicFormat.Raw)
+        receipt["verifier_fingerprint"] = hashlib.sha256(pub_bytes).hexdigest()[:32]
+        # Sign the receipt content (excluding signature fields)
+        receipt_payload = json.dumps(receipt, sort_keys=True, ensure_ascii=False).encode()
+        sig = private_key.sign(receipt_payload)
+        receipt["signature"] = sig.hex()
+        receipt["verifier_pubkey"] = pub_bytes.hex()
+
     receipt_json = json.dumps(receipt, indent=2, ensure_ascii=False)
     safe_filename = (
         image_file.filename.rsplit(".", 1)[0] if "." in image_file.filename else image_file.filename

frontends/web/blueprints/fieldkit.py

@@ -30,9 +30,18 @@ def killswitch():
     if request.method == "POST":
         action = request.form.get("action")
         if action == "fire" and request.form.get("confirm") == "CONFIRM-PURGE":
+            # Require password re-authentication for killswitch
+            from auth import verify_user_password
+
+            password = request.form.get("password", "")
+            username = get_username()
+            if not verify_user_password(username, password):
+                flash("Killswitch requires password confirmation.", "danger")
+                return render_template("fieldkit/killswitch.html")
+
             from soosef.fieldkit.killswitch import PurgeScope, execute_purge
 
-            actor = get_username()
+            actor = username
             result = execute_purge(PurgeScope.ALL, reason="web_ui")
             outcome = "success" if result.fully_purged else "failure"
             failed_steps = ", ".join(name for name, _ in result.steps_failed)