M5: moderation, permissions, channel CRUD, in-app account management

- Server-side moderation & permissions (kick/ban/move/server-mute, channel CRUD).

- Database schema v2: channels, bans; BLAKE2b channel passwords, Argon2id accounts.

- C ABI additions and client-side handling (vc_kick_user, vc_ban_user, vc_set_permission, vc_set_server_mute, vc_move_user, vc_create/edit/delete_channel, vc_create/reset/delete/list_account).

- vccli flags for all M5 operations plus --username/--password auth.

- Four new tests covering permissions, kick/ban/move/mute, admin accounts, channel CRUD.

- Docs: protocol.md envelope updates, security.md channel-password hashing, PROGRESS.md.

core/include/voicecat.h

@@ -127,7 +127,7 @@ typedef enum vc_event_type {
     VC_EVENT_TALK_STATE = 9,       /* user_id, stream_id, u32a = talking(0/1) */
     VC_EVENT_ERROR = 10,           /* result, text */
     VC_EVENT_DISCONNECTED = 11,    /* result, text = reason */
-    /* M4 additions — appended, not inserted, to keep existing values stable. */
+    /* M4 additions — appended, not inserted, to keep existing enum values stable. */
     VC_EVENT_JOIN_RESULT = 12,     /* result (VC_OK/VC_ERR_*), channel_id, text = error on
                                        failure. Reply to vc_join_channel(). */
     VC_EVENT_SERVER_IDENTITY = 13, /* u32a = vc_tofu_status, text = hex-encoded TLS leaf-cert
@@ -136,6 +136,13 @@ typedef enum vc_event_type {
                                        attempt, right after the TLS handshake succeeds. The
                                        connection is held open until vc_confirm_server_identity()
                                        is called. */
+    /* M5 additions — appended, not inserted. */
+    VC_EVENT_GENERIC_RESULT = 14,  /* result, u32a = server error code, text = message. Reply
+                                       to vc_kick_user/vc_ban_user/vc_set_permission/
+                                       vc_move_user/vc_create_channel/vc_edit_channel/
+                                       vc_delete_channel/vc_create_account/vc_reset_password/
+                                       vc_delete_account. */
+    VC_EVENT_ACCOUNT_LIST = 15,    /* Reply to vc_list_accounts. */
 } vc_event_type;
 
 /* TOFU server-identity classification (M4) — see VC_EVENT_SERVER_IDENTITY and
@@ -216,6 +223,30 @@ typedef struct vc_audio_config {
     uint32_t complexity;           /* 0..10 */
 } vc_audio_config;
 
+/* M5: permission bitset (mirrors protocol Permissions). */
+typedef struct vc_permissions {
+    int can_create_temp_channel; /* bool */
+    int can_kick;                /* bool */
+    int can_ban;                 /* bool */
+    int can_move_users;          /* bool */
+    int can_admin_accounts;      /* bool */
+    int is_admin;                /* bool */
+} vc_permissions;
+
+/* M5: channel creation/edition descriptor. */
+typedef struct vc_channel_info {
+    uint32_t id;                  /* 0 = new channel for create */
+    uint32_t parent_id;           /* 0 = root */
+    const char* name;
+    const char* topic;
+    int         password_protected; /* bool */
+    const char* password;           /* nullable; ignored if password_protected == 0 */
+    uint32_t    max_users;          /* 0 = unlimited */
+    uint32_t    sort_order;
+    /* Audio config — 0/NULL fields use server defaults. */
+    vc_audio_config audio;
+} vc_channel_info;
+
 typedef struct vc_device {
     const char* id;
     const char* name;
@@ -370,6 +401,32 @@ VC_API vc_result vc_confirm_server_identity(vc_client* c, int accept /* bool */)
 VC_API vc_result vc_get_server_identity_display(vc_client* c, char* out_buf, size_t buf_cap,
                                                  size_t* out_len);
 
+/* ── M5: Moderation & admin ─────────────────────────────────────────────────
+ * All calls are async; the result arrives as VC_EVENT_GENERIC_RESULT (or
+ * VC_EVENT_ACCOUNT_LIST for vc_list_accounts). They require VC_STATE_CONNECTED and,
+ * on the server side, the appropriate permission. */
+
+VC_API vc_result vc_kick_user(vc_client* c, uint32_t user_id, const char* reason);
+VC_API vc_result vc_ban_user(vc_client* c, uint32_t user_id, const char* reason,
+                             uint64_t expires_unix_ms);
+VC_API vc_result vc_set_permission(vc_client* c, uint32_t user_id,
+                                    const vc_permissions* perms);
+VC_API vc_result vc_set_server_mute(vc_client* c, uint32_t user_id, int muted, int deafened);
+VC_API vc_result vc_move_user(vc_client* c, uint32_t user_id, uint32_t channel_id);
+
+VC_API vc_result vc_create_channel(vc_client* c, const vc_channel_info* info);
+VC_API vc_result vc_edit_channel(vc_client* c, const vc_channel_info* info);
+VC_API vc_result vc_delete_channel(vc_client* c, uint32_t channel_id);
+
+VC_API vc_result vc_create_account(vc_client* c, const char* username, const char* password);
+VC_API vc_result vc_reset_password(vc_client* c, const char* username,
+                                    const char* new_password);
+VC_API vc_result vc_delete_account(vc_client* c, const char* username);
+VC_API vc_result vc_list_accounts(vc_client* c);
+
+/* Pull the caller's own permissions (from the last AuthResult). */
+VC_API vc_result vc_get_permissions(vc_client* c, vc_permissions* out);
+
 #if defined(__cplusplus)
 } /* extern "C" */
 #endif