feat: IssuerAuth verify at AD finalize + issuer pubkey provisioning (M2A.3)

Expands M2A.3 from the original plan because the credential issuer pubkey
had no provisioning path. Adds INS_SET_CREDENTIAL_ISSUER_PUBK = 0x25 to
PersonalizationApplet, bumps CredentialStore FIELD_VERSION 2 -> 3 to add
a 64 B credentialIssuerPubKey slot + set-flag, and pivots
finalizeAccessDocument to run a one-shot CoseVerifier RFC 9052
COSE_Sign1 verify against the staged AD bytes before atomically setting
accessDocumentLen + accessDocumentFinalized + accessDocumentVerified
inside a JCSystem transaction.

PersonalizationApplet holds one CoseVerifier instance constructed at
install (the 768 B CLEAR_ON_DESELECT scratch only allocates once) plus
a 65 B EEPROM scratch for staging the uncompressed issuer pubkey.

Status word mapping:
- missing issuer pubkey at finalize -> SW_CONDITIONS_NOT_SATISFIED (0x6985)
- IssuerAuth signature mismatch     -> SW_DATA_INVALID            (0x6984)
- length out of range               -> SW_WRONG_DATA               (0x6A80)
On verify failure the store stays untouched -- both
accessDocumentFinalized and accessDocumentVerified remain false.

Harness side: TrustArtifacts gains credential_issuer_pub (loaded from
trust_dir/issuer.pem). The orchestrator sends INS 0x25 after the
existing key writes and before the AD chunks so the trust anchor is
staged by the time FINALIZE_AD runs.

Test vector: AD bytes + matching issuer pubkey x||y are hardcoded into
PersonalizationAppletTest from the canonical trustgen artifacts at
/home/work/aliro-trust (272 B AD against a known issuer.pem).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

harness/src/aliro_harness/personalizer/apdus.py

@@ -11,6 +11,7 @@ INS_SET_CRED_PUBK = 0x21
 INS_SET_READER_PUBK = 0x22
 INS_WRITE_ACCESS_DOC = 0x23
 INS_FINALIZE_ACCESS_DOC = 0x24
+INS_SET_CRED_ISSUER_PUBK = 0x25
 INS_COMMIT = 0x2C
 
 # Provisioning AID — must match AliroAids.PROVISIONING in the applet.
@@ -21,6 +22,7 @@ PROVISIONING_AID = bytes.fromhex("A000000909ACCE559901")
 CRED_PRIV_LEN = 32
 CRED_PUBK_LEN = 64
 READER_PUBK_LEN = 64
+CRED_ISSUER_PUBK_LEN = 64
 
 
 def select_provisioning_apdu() -> bytes:
@@ -46,6 +48,16 @@ def set_reader_pubk_apdu(pubk_xy: bytes) -> bytes:
     return _short_apdu(INS_SET_READER_PUBK, 0, 0, pubk_xy)
 
 
+def set_credential_issuer_pubk_apdu(pubk_xy: bytes) -> bytes:
+    """Push the Credential Issuer public key (P-256 x||y, no 0x04 prefix).
+    The applet stages it for IssuerAuth COSE_Sign1 verify at FINALIZE_AD."""
+    if len(pubk_xy) != CRED_ISSUER_PUBK_LEN:
+        raise ValueError(
+            f"credential_issuer_PubK must be {CRED_ISSUER_PUBK_LEN}B (x||y), got {len(pubk_xy)}"
+        )
+    return _short_apdu(INS_SET_CRED_ISSUER_PUBK, 0, 0, pubk_xy)
+
+
 def commit_apdu() -> bytes:
     return bytes([CLA_PROPRIETARY, INS_COMMIT, 0x00, 0x00])