feat(#216): dynamic commands catalog + mid-turn slash command support (#395)

* feat(ws): add commands.catalog RPC constants and data models

* feat(catalog): fetch commands.catalog on WS gateway ready, store in state

* feat(commands): rewrite dispatcher to forward non-local commands via WS command.dispatch

* feat(input): always-visible send button + compact stop icon, allow / commands mid-turn

* test(commands): update tests for WS-based command dispatch

* fix: add missing CommandCatalog + JsonRpcError imports

* fix(test): assert errorMessage instead of messages for unknown command

* chore: remove unused CommandDispatchResponse data class

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/data/ws/CommandModels.kt

@@ -0,0 +1,22 @@
+package com.m57.hermescontrol.data.ws
+
+/**
+ * Response from `commands.catalog` RPC — full catalog of available
+ * slash commands, subcommands, and alias mappings.
+ */
+data class CommandCatalog(
+    val pairs: List<List<String>> = emptyList(),
+    val sub: Map<String, List<String>> = emptyMap(),
+    val canon: Map<String, String> = emptyMap(),
+    val categories: List<CommandCategory> = emptyList(),
+    val skillCount: Int = 0,
+    val warning: String = "",
+)
+
+/**
+ * A named category within the command catalog.
+ */
+data class CommandCategory(
+    val name: String,
+    val pairs: List<List<String>>,
+)

app/src/main/java/com/m57/hermescontrol/data/ws/WsMethods.kt

@@ -2,16 +2,24 @@ package com.m57.hermescontrol.data.ws
 
 /** JSON-RPC method name constants used with [HermesWsClient.send]. */
 object WsMethods {
+    // ── Session ───────────────────────────────────────────────────────────
     const val SESSION_LIST = "session.list"
     const val SESSION_ACTIVE_LIST = "session.active_list"
     const val SESSION_STATUS = "session.status"
     const val SESSION_HISTORY = "session.history"
     const val SESSION_RESUME = "session.resume"
     const val SESSION_CREATE = "session.create"
-    const val PROMPT_SUBMIT = "prompt.submit"
     const val SESSION_INTERRUPT = "session.interrupt"
     const val SESSION_DELETE = "session.delete"
     const val SESSION_TITLE = "session.title"
+
+    // ── Interaction ───────────────────────────────────────────────────────
+    const val PROMPT_SUBMIT = "prompt.submit"
     const val CLARIFY_RESPOND = "clarify.respond"
     const val APPROVAL_RESPOND = "approval.respond"
+
+    // ── Commands catalog ──────────────────────────────────────────────────
+    const val COMMANDS_CATALOG = "commands.catalog"
+    const val COMMAND_DISPATCH = "command.dispatch"
+    const val COMMAND_RESOLVE = "command.resolve"
 }