Add tasks: the crew's shared to-do list

Bots and workspaces each keep a list of work tracked until it's done, and
the bots move it along themselves as they work.

- tasks (one collection per bot or per workspace), task_notes (the
  progress log) and task_media (a deliverable or a reference file, its
  bytes a private media row served at /media/private/<id>)
- statuses todo/doing/blocked/done/cancelled, with blocked_reason while
  only the user can unblock it
- visibility as SQL in src/utils/task-access: a user's own bots and
  workspaces, a run's own list plus its workspaces, everything for the
  coordinator; every tool and endpoint resolves through it
- list_tasks, create_task and update_task on every run, so a chat reply,
  a task and a routine all read the list, log progress and file what they
  produced
- TasksNote on every run and TaskReminderNote in chat, so a greeting or a
  proposed next step brings pending work up in one measured line
- tasks group on the workspace dashboard and a tasks modal in the
  conversation header, sharing one form, row and detail panel
- a bot's or workspace's own chat uploads are read before the delete so
  none are stranded; bot files keep their folder

Also corrects the README's RAM guidance and table alignment.

src/schemas/task-schema.ts

@@ -0,0 +1,75 @@
+import { z } from "zod";
+import { AppData } from "@/src/data/app-data";
+import { TaskMediaKinds, TaskStatuses } from "@/src/dict/task-dict";
+
+const status_values = TaskStatuses.map((status) => status.value) as [string, ...string[]];
+const media_kind_values = TaskMediaKinds.map((kind) => kind.value) as [string, ...string[]];
+
+/**
+ * One collection: a bot's own list or a workspace's shared one. The helper
+ * refuses both or neither (`taskScopeValues`).
+ */
+const scope = {
+    bot_id: z.number().int().positive().optional(),
+    workspace_id: z.number().int().positive().optional(),
+};
+
+export const CreateTaskRequestSchema = z.object({
+    ...scope,
+    title: z.string().trim().min(1).max(AppData.TaskTitleMaxLength),
+    description: z.string().max(AppData.TaskDescriptionMaxLength).optional(),
+    status: z.enum(status_values).optional(),
+});
+
+export const UpdateTaskRequestSchema = z.object({
+    task_id: z.number().int().positive(),
+    title: z.string().trim().min(1).max(AppData.TaskTitleMaxLength).optional(),
+    description: z.string().max(AppData.TaskDescriptionMaxLength).optional(),
+    status: z.enum(status_values).optional(),
+    blocked_reason: z.string().max(AppData.TaskNoteMaxLength).nullable().optional(),
+});
+
+export const DeleteTaskRequestSchema = z.object({
+    task_id: z.number().int().positive(),
+});
+
+export const TaskNoteRequestSchema = z.object({
+    task_id: z.number().int().positive(),
+    text: z.string().trim().min(1).max(AppData.TaskNoteMaxLength),
+});
+
+/**
+ * Linking a file: one from the run's folders (or the user's own uploads)
+ * or a fresh upload, already saved as a private `media` row.
+ */
+export const TaskFileRequestSchema = z.object({
+    task_id: z.number().int().positive(),
+    file_id: z.number().int().positive().optional(),
+    media_id: z.number().int().positive().optional(),
+    kind: z.enum(media_kind_values).optional(),
+});
+
+export const DetachTaskFileRequestSchema = z
+    .object({
+        task_id: z.number().int().positive(),
+        task_media_id: z.number().int().positive().optional(),
+        media_id: z.number().int().positive().optional(),
+    })
+    .refine((body) => Boolean(body.task_media_id || body.media_id), {
+        message: "Which file?",
+    });
+
+/**
+ * Uploading one deliverable straight onto a task, like a chat attachment.
+ */
+export const UploadTaskFileRequestSchema = z.object({
+    task_id: z.number().int().positive(),
+    data_url: z.string().min(1),
+    name: z.string().min(1),
+    kind: z.enum(media_kind_values).optional(),
+});
+
+export type CreateTaskRequest = z.infer<typeof CreateTaskRequestSchema>;
+export type UpdateTaskRequest = z.infer<typeof UpdateTaskRequestSchema>;
+export type TaskNoteRequest = z.infer<typeof TaskNoteRequestSchema>;
+export type TaskFileRequest = z.infer<typeof TaskFileRequestSchema>;