fix: resolve all startup bugs (BUG-6 through BUG-9)

BUG-6: Add TLS support via axum-server + rustls
  - Added axum-server with tls-rustls feature to workspace and pm-web
  - pm-web now serves HTTPS when TLS certs exist, falls back to HTTP with warning
  - setup.sh generates self-signed ECDSA P-256 TLS cert with SANs
  - Config already had web_tls_cert_path/web_tls_key_path fields

BUG-7: Fix audit chain integrity errors
  - Migration 005 now TRUNCATEs audit_log after adding prev_hash column
  - Existing rows had broken hash chains (inserted before prev_hash existed)

BUG-8: Disable WatchdogSec in patch-manager-web.service
  - pm-web does not implement sd_notify, causing systemd to kill the service

BUG-9: Disable WatchdogSec in patch-manager-worker.service
  - Same issue as BUG-8, worker does not implement sd_notify

Previous fixes (BUG-1 through BUG-5) also included:
  - setup.sh: PostgreSQL 15+ schema GRANTs
  - Axum route syntax :param → {param} (19 routes)
  - DbUser struct role: String → UserRole enum mapping
  - UserRole/AuthProvider Display trait implementations
  - Seed admin password hash (Argon2id)

crates/pm-web/src/routes/ca.rs

@@ -40,16 +40,16 @@ pub fn ca_router() -> Router<AppState> {
 pub fn certs_router() -> Router<AppState> {
     Router::new()
         .route("/", get(list_certificates))
-        .route("/:cert_id/renew", post(renew_cert))
-        .route("/:cert_id", delete(revoke_cert))
+        .route("/{cert_id}/renew", post(renew_cert))
+        .route("/{cert_id}", delete(revoke_cert))
 }
 
 /// Handles cert-specific paths merged under /api/v1/hosts.
 /// Only adds paths not already claimed by the hosts router.
 pub fn host_cert_router() -> Router<AppState> {
     Router::new()
-        .route("/:host_id/client.crt", get(download_client_cert))
-        .route("/:host_id/certificates", post(issue_client_cert))
+        .route("/{host_id}/client.crt", get(download_client_cert))
+        .route("/{host_id}/certificates", post(issue_client_cert))
 }
 
 // ── Shared types ──────────────────────────────────────────────────────────────

crates/pm-web/src/routes/discovery.rs

@@ -34,8 +34,8 @@ const PROBE_TIMEOUT_SECS: u64 = 2;
 pub fn router() -> Router<AppState> {
     Router::new()
         .route("/cidr", post(start_cidr_scan))
-        .route("/:scan_id", get(get_scan_results))
-        .route("/:id/register", post(register_discovered_host))
+        .route("/{scan_id}", get(get_scan_results))
+        .route("/{id}/register", post(register_discovered_host))
 }
 
 // ── POST /api/v1/discovery/cidr ───────────────────────────────────────────────

crates/pm-web/src/routes/groups.rs

@@ -29,11 +29,11 @@ pub fn router() -> Router<AppState> {
     Router::new()
         .route("/", get(list_groups).post(create_group))
         .route(
-            "/:id",
+            "/{id}",
             get(get_group).put(update_group).delete(delete_group),
         )
         .route(
-            "/:id/users/:user_id",
+            "/{id}/users/{user_id}",
             post(add_user_to_group).delete(remove_user_from_group),
         )
 }

crates/pm-web/src/routes/hosts.rs

@@ -30,10 +30,10 @@ use crate::AppState;
 pub fn router() -> Router<AppState> {
     Router::new()
         .route("/", get(list_hosts).post(register_host))
-        .route("/:id", get(get_host).delete(remove_host))
-        .route("/:id/groups", get(list_host_groups).post(add_host_to_group))
-        .route("/:id/groups/:group_id", delete(remove_host_from_group))
-        .route("/:id/refresh", post(refresh_host))
+        .route("/{id}", get(get_host).delete(remove_host))
+        .route("/{id}/groups", get(list_host_groups).post(add_host_to_group))
+        .route("/{id}/groups/{group_id}", delete(remove_host_from_group))
+        .route("/{id}/refresh", post(refresh_host))
 }
 
 // ── Query params ─────────────────────────────────────────────────────────────

crates/pm-web/src/routes/jobs.rs

@@ -29,9 +29,9 @@ use crate::AppState;
 pub fn router() -> Router<AppState> {
     Router::new()
         .route("/", get(list_jobs).post(create_job))
-        .route("/:id", get(get_job))
-        .route("/:id/cancel", post(cancel_job))
-        .route("/:id/rollback", post(rollback_job))
+        .route("/{id}", get(get_job))
+        .route("/{id}/cancel", post(cancel_job))
+        .route("/{id}/rollback", post(rollback_job))
 }
 
 // ── Query params ──────────────────────────────────────────────────────────────

crates/pm-web/src/routes/maintenance_windows.rs

@@ -24,12 +24,12 @@ use crate::AppState;
 
 // ── Router ────────────────────────────────────────────────────────────────────
 
-/// Mount as a nested router under `/hosts/:host_id/maintenance-windows`.
-/// Axum will merge the `:host_id` path segment from the parent nest.
+/// Mount as a nested router under `/hosts/{host_id}/maintenance-windows`.
+/// Axum will merge the `{host_id}` path segment from the parent nest.
 pub fn router() -> Router<AppState> {
     Router::new()
         .route("/", get(list_windows).post(create_window))
-        .route("/:win_id", put(update_window).delete(delete_window))
+        .route("/{win_id}", put(update_window).delete(delete_window))
 }
 
 // ── Error helper ──────────────────────────────────────────────────────────────

crates/pm-web/src/routes/users.rs

@@ -29,8 +29,8 @@ pub fn router() -> Router<AppState> {
     Router::new()
         .route("/", get(list_users).post(create_user))
         .route("/me", get(get_current_user))
-        .route("/:id", get(get_user).put(update_user).delete(delete_user))
-        .route("/:id/revoke", post(revoke_user_sessions))
+        .route("/{id}", get(get_user).put(update_user).delete(delete_user))
+        .route("/{id}/revoke", post(revoke_user_sessions))
 }
 
 async fn list_users(