fix: honest remediation batch 3 - fix broken claims and real Argon2id

Previous commits marked findings as ✅ that were actually superficial or
broken. This commit fixes the real problems honestly.

Real fixes:
- Argon2id KDF: Fixed via preseed partman/early_command that patches
  partman-crypto's cryptsetup luksFormat to include --pbkdf argon2id.
  Previous luks-kdf-configure.sh "auto-conversion" was dead code
  (cryptsetup luksConvertKey needs stdin passphrase, nothing provides it).
  Now the hook is an honest verifier, not a fake converter.
- src/security-hardening.sh: Removed sshd_config generation entirely
  (was still generating it despite claiming client-only)
- AIDE init: Removed || true error swallowing, now reports failures
- COMPLIANCE.md: Marked CMMC L3 and FedRAMP as aspirational targets
  with honest explanation of what's missing (3PAO, org controls)
- VERIFICATION-REPORT.md: Added self-review warning about contradictions,
  fixed wrong preseed path (config/preseed.cfg → includes.installer/)
- Removed phantom knel-compliance-check.sh reference from COMPLIANCE.md
- encryption-setup.sh: README now says "Argon2id (via early_command)"
  instead of bare "Argon2id" which was false
- demo.preseed.cfg: Added same Argon2id early_command
- Added .dockerignore (was missing)
- Fixed .gitignore *key* pattern (too broad, matched keyboard.conf etc)

Still remaining (honest assessment):
- C-06: Git history scrub (needs git-filter-repo, destructive)
- H-09: Build cache integrity (design work needed)
- M-11: Docker base digest pinning
- Phase 3: Test suite overhaul (85% grep-based, not behavioral)
- Phase 4: Documentation cleanup (threat model, etc)
- ISO NOT rebuilt since fixes

786 tests pass, 0 shellcheck warnings.

💘 Generated with Crush

Assisted-by: GLM-5.1 via Crush <crush@charm.land>

config/hooks/installed/luks-kdf-configure.sh

@@ -1,17 +1,15 @@
 #!/bin/bash
-# LUKS KDF configuration hook - Auto-convert PBKDF2 to Argon2id
-# Addresses C-01: Argon2id KDF not actually enforced
-#
-# Debian partman-crypto creates LUKS2 with PBKDF2 by default.
-# This hook automatically converts to Argon2id during installation,
-# before the system boots for the first time.
+# LUKS KDF verification hook
+# PRD FR-001 requires Argon2id. The preseed early_command patches
+# partman-crypto to use --pbkdf argon2id at format time. This hook
+# verifies the conversion succeeded and creates fallback tools if not.
 #
 # Reference: PRD.md FR-001, security-model.md
 # Copyright 2026 Known Element Enterprises LLC
 # License: GNU Affero General Public License v3.0 only
 set -euo pipefail
 
-echo "Configuring LUKS KDF - auto-converting to Argon2id..."
+echo "Verifying LUKS KDF configuration..."
 
 # Find the LUKS device
 LUKS_DEVICE=""
@@ -22,42 +20,24 @@ for dev in /dev/sda3 /dev/nvme0n1p3 /dev/nvme1n1p3 /dev/vda3; do
     fi
 done
 
-# Also try lsblk discovery
 if [ -z "$LUKS_DEVICE" ] && command -v lsblk >/dev/null 2>&1; then
     LUKS_DEVICE=$(lsblk -lnpo NAME,FSTYPE 2>/dev/null | awk '$2 == "crypto_LUKS" {print $1; exit}')
 fi
 
 if [ -z "$LUKS_DEVICE" ]; then
-    echo "WARNING: No LUKS device found for KDF conversion"
-    echo "Creating manual conversion helper instead..."
+    echo "WARNING: No LUKS device found for KDF verification"
 else
     echo "Found LUKS device: $LUKS_DEVICE"
-
-    # Check current KDF
     CURRENT_KDF=$(cryptsetup luksDump "$LUKS_DEVICE" 2>/dev/null | grep -E "^\s+KDF:" | head -1 | awk '{print $2}' || echo "unknown")
     echo "Current KDF: $CURRENT_KDF"
 
     if [ "$CURRENT_KDF" = "argon2id" ]; then
-        echo "KDF is already Argon2id - no conversion needed."
+        echo "KDF verification PASSED: Argon2id confirmed"
         touch /var/lib/knel-kdf-optimized
     else
-        echo "Converting KDF from $CURRENT_KDF to Argon2id..."
-        echo "This requires the encryption passphrase set during installation."
-
-        # Attempt non-interactive conversion
-        # The user's passphrase was just set during install and is in the installer env
-        if cryptsetup luksConvertKey "$LUKS_DEVICE" --pbkdf argon2id \
-            --pbkdf-memory 524288 --pbkdf-parallel 4 --pbkdf-iterations 4 2>/dev/null; then
-            echo "SUCCESS: KDF converted to Argon2id"
-            touch /var/lib/knel-kdf-optimized
-
-            # Verify
-            NEW_KDF=$(cryptsetup luksDump "$LUKS_DEVICE" 2>/dev/null | grep -E "^\s+KDF:" | head -1 | awk '{print $2}')
-            echo "Verified KDF: $NEW_KDF"
-        else
-            echo "WARNING: Automatic KDF conversion failed (likely passphrase prompt)"
-            echo "Manual conversion will be prompted on first login."
-        fi
+        echo "WARNING: KDF is $CURRENT_KDF, expected argon2id"
+        echo "The early_command patch may not have applied."
+        echo "Run /usr/local/bin/convert-luks-kdf.sh after first boot to convert."
     fi
 fi