Projects: shareable, registry-backed, container-mounted; drop ticket board

Rework projects from single-user leftovers into shareable endeavours.

- DB: move `projects` from the owner bucket to the registry (system.db,
  not encrypted); add `owner_user_id` + `slug` (drop free `path`); new
  `project_members(project_id, user_id, can_write)` mirroring
  `shared_folder_members`. Drop `project_tickets` entirely. Only user↔agent
  conversations stay encrypted (per-user DB) — each member keeps a private
  project chat. Registry home dissolves the cross-DB-FK problem.
- Filesystem/container: on disk `{WD}/projects/{owner_userid}/{slug}`,
  agent/container path `projects/{owner_username}/{slug}`. Two-segment routing
  in UserFs (ProjectMount + host_base_and_tail arm) and a second loop in
  build_user_fs; read-only members get a :ro mount. Reuse the shared-folder
  remount machinery (refresh_user_shared_folders -> refresh_user_mounts).
- Remove the ticket system: ProjectTicketManager, UserContext.tickets, its
  wiring, and the project_tickets references in scheduled_jobs/cron.
- API: repoint handlers to the registry pool + membership scoping. Sharing is
  self-service — owner or any write-member may add/remove members and set
  read/write; only the owner deletes; the owner cannot be removed. New
  POST/DELETE /api/projects/{id}/members[/{user_id}]. Seed `@fs_any allow
  projects/*`; build_runtime_run_context sets working_directory to the agent
  path and drops the host-path allow_fs_writes.
- Frontend: create form without the free path field, owner/read-write badges;
  the detail page becomes header + description + sharing panel + Open chat + a
  file-explorer placeholder (the future primary surface). i18n en/it/fr.

web/components/projects/project-list.js

@@ -33,7 +33,7 @@ export class ProjectListSection extends LightElement {
   }
 
   _emptyForm() {
-    return { name: '', path: '', description: '' };
+    return { name: '', description: '' };
   }
 
   async load() {
@@ -54,7 +54,7 @@ export class ProjectListSection extends LightElement {
   }
 
   _openEdit(project) {
-    this._form  = { name: project.name, path: project.path, description: project.description ?? '' };
+    this._form  = { name: project.name, description: project.description ?? '' };
     this._error = null;
     this._modal = { mode: 'edit', project };
   }
@@ -135,13 +135,6 @@ export class ProjectListSection extends LightElement {
                 .value=${this._form.name}
                 @input=${e => this._setField('name', e.target.value)} />
             </div>
-            <div class="mb-3">
-              <label class="form-label fw-semibold" style="font-size:0.82rem">${t('projects.modal.path')}</label>
-              <input type="text" class="form-control form-control-sm" required
-                placeholder=${t('projects.modal.path_ph')}
-                .value=${this._form.path}
-                @input=${e => this._setField('path', e.target.value)} />
-            </div>
             <div class="mb-4">
               <label class="form-label fw-semibold" style="font-size:0.82rem">${t('projects.modal.desc')}</label>
               <textarea class="form-control form-control-sm" rows="2"
@@ -170,17 +163,26 @@ export class ProjectListSection extends LightElement {
         <div class="project-card-header">
           <div class="project-card-title">${project.name}</div>
           <div class="project-card-actions" @click=${e => e.stopPropagation()}>
-            <button class="project-card-icon-btn" title=${t('projects.action.edit')}
-              @click=${() => this._openEdit(project)}>
-              <i class="bi bi-pencil"></i>
-            </button>
-            <button class="project-card-icon-btn project-card-icon-btn--danger" title=${t('projects.action.delete')}
-              @click=${() => this._delete(project)}>
-              <i class="bi bi-trash"></i>
-            </button>
+            ${project.can_write ? html`
+              <button class="project-card-icon-btn" title=${t('projects.action.edit')}
+                @click=${() => this._openEdit(project)}>
+                <i class="bi bi-pencil"></i>
+              </button>` : nothing}
+            ${project.is_owner ? html`
+              <button class="project-card-icon-btn project-card-icon-btn--danger" title=${t('projects.action.delete')}
+                @click=${() => this._delete(project)}>
+                <i class="bi bi-trash"></i>
+              </button>` : nothing}
           </div>
         </div>
-        <div class="project-card-path"><i class="bi bi-folder2 me-1"></i>${project.path}</div>
+        <div class="project-card-path">
+          ${project.is_owner
+            ? html`<span class="badge text-bg-light"><i class="bi bi-person me-1"></i>${t('projects.badge.owned')}</span>`
+            : html`<span class="badge text-bg-light"><i class="bi bi-people me-1"></i>${t('projects.badge.shared_by', { name: project.owner_name })}</span>`}
+          ${!project.can_write
+            ? html`<span class="badge text-bg-light ms-1" title=${t('projects.badge.readonly')}><i class="bi bi-eye"></i></span>`
+            : nothing}
+        </div>
         ${project.description
           ? html`<div class="project-card-desc">${project.description}</div>`
           : nothing}