chore: rename project coven → hack-house ⛧

Rebrand the Rust client crate (coven/ → hh/, package+binary "hack-house"),
README, CLI strings, and branch (coven → hack-house). Gitea repo renamed
cmd-chat → hack-house to match. Crypto/server logic unchanged; selftest +
golden-vector test still green, binary is now `hack-house`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

hh/tools/gen_vectors.py

@@ -0,0 +1,32 @@
+import srp, srp._pysrp as p, hashlib, binascii
+srp.rfc5054_enable()
+# force pure-python to match (and check active backend)
+import srp as S
+print("# backend:", S._mod.__name__)
+H=hashlib.sha256
+user=b"chat"; pw=b"labtest"
+salt=bytes.fromhex("0a1b2c3d")             # fixed 4-byte salt
+a=bytes.fromhex(("11"*256))                # fixed 256-byte a (high bit set via 0x11.. ok? need high bit) 
+a=bytes([0x80])+bytes.fromhex("22"*255)    # ensure high bit set, 256 bytes
+b=bytes([0x80])+bytes.fromhex("33"*255)
+# verifier from known salt: replicate create_salted_verification_key internals with fixed salt
+N,g=p.get_ng(p.NG_2048,None,None)
+x=p.gen_x(H, salt, user, pw)
+v=pow(g,x,N)
+v_bytes=p.long_to_bytes(v)
+usr=p.User(user,pw,hash_alg=p.SHA256,ng_type=p.NG_2048,bytes_a=a)
+I,A=usr.start_authentication()
+svr=p.Verifier(user,salt,v_bytes,A,hash_alg=p.SHA256,ng_type=p.NG_2048,bytes_b=b)
+s2,B=svr.get_challenge()
+M=usr.process_challenge(salt,B)
+HAMK=svr.verify_session(M)
+usr.verify_session(HAMK)
+def hx(x): return binascii.hexlify(x).decode()
+print("N_bits", N.bit_length())
+print("salt", hx(salt))
+print("A", hx(A))
+print("B", hx(B))
+print("M", hx(M))
+print("HAMK", hx(HAMK))
+print("K", hx(usr.K))
+print("authok", usr.authenticated())