Consolidate stegasoo and verisoo into soosef monorepo

Merge stegasoo (v4.3.0, steganography) and verisoo (v0.1.0, attestation)
as subpackages under soosef.stegasoo and soosef.verisoo. This eliminates
cross-repo coordination and enables atomic changes across the full stack.

- Copy stegasoo (34 modules) and verisoo (15 modules) into src/soosef/
- Convert all verisoo absolute imports to relative imports
- Rewire ~50 import sites across soosef code (cli, web, keystore, tests)
- Replace stegasoo/verisoo pip deps with inlined code + pip extras
  (stego-dct, stego-audio, attest, web, api, cli, fieldkit, all, dev)
- Add _availability.py for runtime feature detection
- Add unified FastAPI mount point at soosef.api
- Copy and adapt tests from both repos (155 pass, 1 skip)
- Drop standalone CLI/web frontends; keep FastAPI as optional modules
- Both source repos tagged pre-monorepo-consolidation on GitHub

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

frontends/web/blueprints/attest.py

@@ -21,7 +21,7 @@ bp = Blueprint("attest", __name__)
 
 def _get_storage():
     """Get verisoo LocalStorage pointed at soosef's attestation directory."""
-    from verisoo.storage import LocalStorage
+    from soosef.verisoo.storage import LocalStorage
 
     from soosef.paths import ATTESTATIONS_DIR
 
@@ -30,7 +30,7 @@ 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.verisoo.crypto import load_private_key
 
     from soosef.paths import IDENTITY_PRIVATE_KEY
 
@@ -139,7 +139,7 @@ def attest():
             auto_exif = request.form.get("auto_exif", "on") == "on"
 
             # Create the attestation
-            from verisoo.attestation import create_attestation
+            from soosef.verisoo.attestation import create_attestation
 
             attestation = create_attestation(
                 image_data=image_data,
@@ -167,7 +167,7 @@ def attest():
 
             # Save our own identity so we can look it up during verification
             from cryptography.hazmat.primitives.serialization import Encoding, PublicFormat
-            from verisoo.models import Identity
+            from soosef.verisoo.models import Identity
 
             pub_key = private_key.public_key()
             pub_bytes = pub_key.public_bytes(Encoding.Raw, PublicFormat.Raw)
@@ -217,7 +217,7 @@ def _verify_image(image_data: bytes) -> dict:
         matches        — list of match dicts (record, match_type, distances, attestor_name)
         record_count   — total records searched
     """
-    from verisoo.hashing import compute_all_distances, hash_image, is_same_image
+    from soosef.verisoo.hashing import compute_all_distances, hash_image, is_same_image
 
     query_hashes = hash_image(image_data)
     storage = _get_storage()