feat: Agent distribution with secure enrollment from the control panel

One universal Windows Agent package per version (agent_releases: version/
platform/architecture/sha256/status DRAFT|PUBLISHED|REVOKED; the binary
lives on a local release-storage volume, never in PostgreSQL). An operator
creates a pending installation (agent_enrollments) from Agents / Servidores
-> + Nova instalação, then either downloads it directly or generates a
one-time HTTPS link (short TTL, single use). Either path streams the
package plus a freshly minted enrollment.json whose token is never written
to storage in plaintext, only its SHA-256 hash. On the client host,
gti-agent.ps1 install-auto verifies the bundle's SHA-256, refuses a non-
HTTPS Hub, enrolls via POST /v1/agents/enroll (deleting the enrollment
token immediately after, success or failure), writes an ACL-restricted
.env with the newly issued permanent Agent token, and registers the
Windows Service without starting it (Firebird stays unconfigured on
purpose). Idempotent, replay-proof, rate-limited per IP, fully audited,
never logs a secret.

Migration 0022_agent_releases_enrollment (verified fresh-DB ==
upgrade-from-0021 by pg_dump diff). GTI_FISCAL_VERSION/AGENT_VERSION
bumped to 1.1.0 as the single source of truth across code, packages, the
release manifest and every published AgentRelease row.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

central/app/models.py

@@ -366,6 +366,59 @@ class AuditEvent(Base):
     occurred_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), index=True)
 
 
+class AgentRelease(Base):
+    """A published build of the Windows Agent package. The universal binary/zip is
+    shared by every installation; storage_path points at it on the Hub's local
+    release storage (never inside PostgreSQL)."""
+    __tablename__ = "agent_releases"
+    __table_args__ = (UniqueConstraint("version", "platform", "architecture", name="uq_agent_release_version"),)
+    id: Mapped[int] = mapped_column(primary_key=True)
+    version: Mapped[str] = mapped_column(String(32), index=True)
+    platform: Mapped[str] = mapped_column(String(16), default="windows", server_default="windows")
+    architecture: Mapped[str] = mapped_column(String(16), default="x64", server_default="x64")
+    filename: Mapped[str] = mapped_column(String(255))
+    size_bytes: Mapped[int] = mapped_column(Integer)
+    sha256: Mapped[str] = mapped_column(String(64), index=True)
+    storage_path: Mapped[str] = mapped_column(String(512))
+    status: Mapped[str] = mapped_column(String(16), default="DRAFT", server_default="DRAFT", index=True)  # DRAFT | PUBLISHED | REVOKED
+    release_notes: Mapped[str | None] = mapped_column(Text, nullable=True)
+    created_by: Mapped[int | None] = mapped_column(ForeignKey("admin_users.id"), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
+    published_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+
+
+class AgentEnrollment(Base):
+    """A pending (or completed) Agent installation: created by an operator in the
+    control panel before any real Agent exists. Carries two distinct, hashed,
+    single-use, short-TTL secrets — a download token (for the shareable package
+    link) and an enrollment token (embedded in the bundle, consumed once by
+    POST /v1/agents/enroll). Never stores either secret in plaintext."""
+    __tablename__ = "agent_enrollments"
+    id: Mapped[int] = mapped_column(primary_key=True)
+    enrollment_uuid: Mapped[str] = mapped_column(String(36), unique=True, index=True)
+    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id"), index=True)
+    display_name: Mapped[str] = mapped_column(String(160))
+    expected_hostname: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    release_id: Mapped[int] = mapped_column(ForeignKey("agent_releases.id"), index=True)
+    status: Mapped[str] = mapped_column(String(16), default="PENDING", server_default="PENDING", index=True)
+    # PENDING | LINK_CREATED | DOWNLOADED | ENROLLED | EXPIRED | REVOKED | FAILED
+    created_by: Mapped[int | None] = mapped_column(ForeignKey("admin_users.id"), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
+    download_token_hash: Mapped[str | None] = mapped_column(String(64), nullable=True)
+    download_token_expires_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    download_max_uses: Mapped[int] = mapped_column(Integer, default=1, server_default="1")
+    download_uses: Mapped[int] = mapped_column(Integer, default=0, server_default="0")
+    downloaded_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    enrollment_token_hash: Mapped[str | None] = mapped_column(String(64), nullable=True)
+    enrollment_token_expires_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    enrollment_used_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    machine_fingerprint_seen: Mapped[str | None] = mapped_column(String(128), nullable=True)
+    hostname_seen: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    hostname_mismatch: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
+    agent_id: Mapped[int | None] = mapped_column(ForeignKey("agents.id"), nullable=True, index=True)
+    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+
+
 class Job(Base):
     __tablename__ = "jobs"
     id: Mapped[int] = mapped_column(primary_key=True)