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/release_storage.py

@@ -0,0 +1,35 @@
+"""Local, non-web-served storage for published Agent release zips.
+
+Binaries never live in PostgreSQL — only their metadata (AgentRelease rows)
+do. The storage root is a plain directory outside `central/static`, so it is
+never directly reachable by a URL; every download goes through the
+authenticated or token-gated routes in agent_distribution.py.
+"""
+from pathlib import Path
+
+from . import config
+
+_SAFE_COMPONENT = __import__("re").compile(r"^[A-Za-z0-9._-]+$")
+
+
+def storage_root() -> Path:
+    root = Path(config.settings.agent_release_storage_path)
+    root.mkdir(parents=True, exist_ok=True)
+    return root
+
+
+def release_filename(version: str, platform: str, architecture: str) -> str:
+    return f"GTIFiscalAgent-{version}-{platform}-{architecture}.zip"
+
+
+def safe_path_for(storage_path: str) -> Path:
+    """Resolve a release's storage_path against the root, refusing anything
+    that could escape it (path traversal). storage_path is DB-controlled
+    (never derived from an HTTP request), but this stays fail-closed anyway."""
+    if not storage_path or not _SAFE_COMPONENT.match(storage_path):
+        raise ValueError(f"unsafe release storage_path: {storage_path!r}")
+    root = storage_root().resolve()
+    candidate = (root / storage_path).resolve()
+    if candidate.parent != root:
+        raise ValueError(f"release storage_path escapes storage root: {storage_path!r}")
+    return candidate