feat(ai): add remote coding agent sessions for SSH hosts (#1545)

* feat(ai): add host coding agent sessions with configured providers

* Wait for agent initialization and shutdown before resuming sessions

* Keep Pi transcripts outside its configuration migration directory

* Cover Pi session directory separation

* Update core permission catalog expectations for remote agents

* Install remote agent runtimes from verified official sources

* Wait for the identity panel credentials request in its test

* Add scoped SSH forwarding setup for remote agents

* Verify forwarding setup through a fresh SSH connection

* Bound the SSH forwarding verification timeout

* Return the forwarding verification callback result

* fix(ai): support agent send and interrupt keyboard shortcuts

* feat(ai): add agent queues attachments worktrees and session recovery

* fix(ai): handle deleted workspace paths and duplicate status events

* fix(ai): accept file references in root workspaces

* fix(ai): refresh paused queues after agent errors

* fix(ai): store agent sessions in plugin tables and lock down OpenCode

Agent sessions lived in a single ctx.kv value holding up to 2000 events,
which passed the 256 KB kv limit within minutes of a normal run. Every
save after that failed, so history, nativeId, queue and archive changes
were lost and every event wrote a kv audit row.

Sessions, events and queued prompts now have their own tables. A running
agent appends events in batches at most once a second with a lazy save;
session and queue changes save immediately. Prompts, drafts and stored
event text are capped in UTF-8 bytes to fit MySQL TEXT. kv:own is no
longer requested.

The OpenCode server now requires a per-session password, so other local
accounts on the host cannot drive the agent through its loopback port.

* test(upgrade): include agent session tables in the reviewed upgrade SQL

plugins/ai/migrations/mysql/0003_agent_sessions.sql

@@ -0,0 +1,46 @@
+-- ai 0003: agent_sessions
+-- Generated by termix-plugin migrations. Review before committing.
+
+CREATE TABLE IF NOT EXISTS `p_ai_agent_sessions` (
+  `id` int AUTO_INCREMENT PRIMARY KEY,
+  `session_id` varchar(36) NOT NULL UNIQUE,
+  `user_id` varchar(255) NOT NULL,
+  `host_id` int NOT NULL,
+  `provider_id` int NOT NULL,
+  `agent` varchar(32) NOT NULL,
+  `model` text NOT NULL,
+  `cwd` text NOT NULL,
+  `executable` text NOT NULL,
+  `native_id` text,
+  `title` text,
+  `archived` boolean NOT NULL DEFAULT false,
+  `queue_paused` boolean NOT NULL DEFAULT false,
+  `draft` text,
+  `attachments` text NOT NULL DEFAULT ('[]'),
+  `updated_at` text NOT NULL,
+  FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE
+);
+CREATE INDEX `idx_ai_agent_sessions_user` ON `p_ai_agent_sessions` (`user_id`);
+CREATE TABLE IF NOT EXISTS `p_ai_agent_events` (
+  `id` int AUTO_INCREMENT PRIMARY KEY,
+  `session_id` varchar(36) NOT NULL,
+  `user_id` varchar(255) NOT NULL,
+  `seq` int NOT NULL,
+  `kind` varchar(16) NOT NULL,
+  `text` text NOT NULL,
+  `request_id` text,
+  `choices` text,
+  FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE
+);
+CREATE UNIQUE INDEX `idx_ai_agent_events_session_seq` ON `p_ai_agent_events` (`session_id`, `seq`);
+CREATE TABLE IF NOT EXISTS `p_ai_agent_queue` (
+  `id` int AUTO_INCREMENT PRIMARY KEY,
+  `session_id` varchar(36) NOT NULL,
+  `user_id` varchar(255) NOT NULL,
+  `prompt_id` varchar(36) NOT NULL,
+  `position` int NOT NULL,
+  `text` text NOT NULL,
+  `attachment_ids` text NOT NULL DEFAULT ('[]'),
+  FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE
+);
+CREATE INDEX `idx_ai_agent_queue_session` ON `p_ai_agent_queue` (`session_id`, `position`);