refactor: daemon collectors, thin webui proxies, pure config reads

- move state collectors from lib/state.py to daemon/collectors/ (7
  modules, registration side-effect; daemon/server.py imports the
  package before the first populate())
- webui/api: new daemon_route() decorator factory in common.py
  collapses the try/except daemon-proxy boilerplate in all 8
  blueprints (rules/params/body/transform keep responses identical)
- firewall: interface-coverage invariant — config is the source of
  truth for zone interfaces (absent key = empty, no hands-off
  zones); pure validate_coverage() enforced at save (400) and apply
  (409, force: true overrides), top-level `unmanaged` exemption
- lib: get_config() reads are now pure (no dir creation or writes);
  new lib/bootstrap.py creates runtime dirs and persists the
  one-shot nginx legacy migration at daemon start, after
  system_import (lib.nginx.migrate_config_file)
- lib/common: compute_pending() apply-bookkeeping helper
- daemon: emit_and_refresh() handler helper; refresh_state(bump=) so
  /status/refresh no longer bumps versions (poll/mutation only)
- acme: move --log last so acme.sh never treats a real arg as the
  log-file argument
- docs: AGENTS.md, config.md, state-model.md, api.md updated;
  HARDEN.md dropped (plan implemented); apply-confirm force wording

Tests: 917 passed; ruff check + format clean.

lib/firewall.py

@@ -7,6 +7,7 @@ All privileged commands are handled by daemon/handlers/firewall.py.
 
 import logging
 from collections.abc import Sequence
+from copy import deepcopy
 from datetime import UTC, datetime
 from pathlib import Path
 from typing import Any
@@ -327,9 +328,16 @@ def _ensure_config_file() -> None:
 
 
 def get_config() -> dict[str, Any]:
-    """Return the declarative config from ``config/firewall/config.json``."""
-    _ensure_config_file()
-    return load_json(CONFIG_FILE)
+    """Return the declarative config from ``config/firewall/config.json``.
+
+    Pure read — never writes. Returns the in-memory default when the file
+    is missing; the file is materialized on the first ``save_config`` (or
+    by the system-config import on first start).
+    """
+    raw = load_json(CONFIG_FILE)
+    if not raw:
+        return deepcopy(DEFAULT_CONFIG)
+    return raw
 
 
 def save_config(cfg: dict[str, Any]) -> None:
@@ -370,11 +378,10 @@ def _compute_pending_changes(
     Pure function — no subprocess calls. Caller is responsible for providing
     live state (typically from the daemon).
 
-    The interfaces diff is only reported for zones whose config explicitly
-    carries an ``interfaces`` key; zones with the key absent are hands-off
-    (apply keeps their live interfaces), so diffing them would advertise
-    changes that never happen. Likewise the target diff is only reported when
-    the config carries an explicit target that normalizes to something other
+    The config is the source of truth for zone interfaces: an absent
+    ``interfaces`` key counts as an empty list, so every config zone is
+    diffed on interfaces. Likewise the target diff is only reported when the
+    config carries an explicit target that normalizes to something other
     than ``default`` — an absent key or a ``default``-normalizing value is
     unmanaged (apply never re-sets it). Services, masquerade, rich rules and
     forward ports are reported for all config zones.
@@ -387,18 +394,19 @@ def _compute_pending_changes(
     for zone_name, zone_cfg in cfg_zones.items():
         live_zone = live_zones.get(zone_name, {})
 
-        if "interfaces" in zone_cfg:
-            cfg_ifaces = set(zone_cfg.get("interfaces", []))
-            live_ifaces = set(live_zone.get("interfaces", []))
-            if cfg_ifaces != live_ifaces:
-                changes.append(
-                    {
-                        "zone": zone_name,
-                        "type": "interfaces",
-                        "config": sorted(cfg_ifaces),
-                        "live": sorted(live_ifaces),
-                    }
-                )
+        # The config is the source of truth for zone interfaces: an absent
+        # key counts as an empty list, so every config zone is diffed.
+        cfg_ifaces = set(zone_cfg.get("interfaces", []))
+        live_ifaces = set(live_zone.get("interfaces", []))
+        if cfg_ifaces != live_ifaces:
+            changes.append(
+                {
+                    "zone": zone_name,
+                    "type": "interfaces",
+                    "config": sorted(cfg_ifaces),
+                    "live": sorted(live_ifaces),
+                }
+            )
 
         cfg_services = set(zone_cfg.get("services", []))
         live_services = set(live_zone.get("services", []))
@@ -488,6 +496,49 @@ def _compute_pending_changes(
     }
 
 
+def validate_coverage(fw_cfg: dict[str, Any], net_cfg: dict[str, Any]) -> list[str]:
+    """Return network-managed interfaces with no firewall zone coverage.
+
+    Pure — compares the declarative firewall config against the network
+    config; no live state. A managed interface is covered when it appears in
+    some zone's ``interfaces`` list (an absent key counts as empty), or is
+    explicitly declared in the top-level ``unmanaged`` list. ``lo`` and
+    ``wg*`` interfaces are never guarded (VPN zones are managed by the
+    WireGuard sync; loopback is normally zoneless).
+
+    Args:
+        fw_cfg: Firewall declarative config (``zones`` plus optional
+            top-level ``unmanaged`` list).
+        net_cfg: Network config (``interfaces`` mapping).
+
+    Returns:
+        Sorted list of uncovered interface names; empty when the config is
+        valid.
+    """
+    managed = [
+        name
+        for name in net_cfg.get("interfaces", {})
+        if name != "lo" and not name.startswith("wg")
+    ]
+    if not managed:
+        return []
+    covered: set[str] = set()
+    for zone_cfg in fw_cfg.get("zones", {}).values():
+        if isinstance(zone_cfg, dict):
+            covered.update(
+                i for i in zone_cfg.get("interfaces", []) if isinstance(i, str)
+            )
+    unmanaged_raw = fw_cfg.get("unmanaged", [])
+    unmanaged = (
+        {i for i in unmanaged_raw if isinstance(i, str)}
+        if isinstance(unmanaged_raw, list)
+        else set()
+    )
+    return sorted(
+        name for name in managed if name not in covered and name not in unmanaged
+    )
+
+
 def config_pending(state: dict[str, Any]) -> dict[str, Any]:
     """Compare declarative config against firewalld live state, return diff.
 
@@ -554,4 +605,5 @@ __all__ = [
     "load_backup",
     "save_backup",
     "save_config",
+    "validate_coverage",
 ]