feat(web): dashboard session deletion and E2E coverage for issue #150

- Add DeleteSessionAsync to ISessionStore/SessionService (unpublish portfolio card,
  remove bot-created empty forum topic, update batch message).
- Add DeleteSessionForCurrentUserAsync to AuthorizedSessionService with audit log.
- Add delete button + confirmation dialog to GroupDetails.razor.
- Extend dashboard Playwright tests with edit persistence and delete verification.
- Update AuthorizedSessionServiceTests with delete authorization coverage.
- Mark issue #150 as done in tests/e2e/README.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/e2e/README.md

@@ -12,10 +12,10 @@ Tracked as a Gitea milestone: [E2E Automation](https://git.codeanddice.ru/toutsu
 | #144 | initData / Login Widget helper for mock Telegram auth | ✅ Done |
 | #145 | Playwright tests for Blazor dashboard with mocked Telegram auth | ✅ Done |
 | #146 | Telegram user client (MTProto) | ✅ Done |
-| #147 | Automate group creation and bot invitation | 🚧 In progress |
-| #148 | Scenario: /newsession from creation to publication | ⏳ Planned |
-| #149 | Join/leave, waitlist, reschedule and notification scenarios | ⏳ Planned |
-| #150 | Dashboard display and editing verification | ⏳ Planned |
+| #147 | Automate group creation and bot invitation | ✅ Done |
+| #148 | Scenario: /newsession from creation to publication | ✅ Done |
+| #149 | Join/leave, waitlist, reschedule and notification scenarios | ✅ Done |
+| #150 | Dashboard display and editing verification | ✅ Done |
 | #151 | Console runner and cleanup | ⏳ Planned |
 
 ## Structure
@@ -36,11 +36,14 @@ tests/e2e/
     ├── GmRelay.E2E.Runner.csproj   # C# console runner using WTelegramClient (MTProto)
     ├── Program.cs                  # Entry point for quick manual checks
     ├── TelegramUserClient.cs       # Reusable MTProto user client wrapper
-    ├── GroupSetupScenario.cs       # Create group + invite bot + verify /start
-    ├── RunnerConfig.cs             # Configuration model
-    ├── .env.example                # Required environment variables
-    ├── .gitignore                  # Ignore .env and session files
-    └── packages.lock.json          # Restored lock file for the runner project
+    ├── GroupSetupScenario.cs                # Create group + invite bot + verify /start
+    ├── NewSessionScenario.cs                # Walk the /newsession wizard end-to-end
+    ├── JoinLeaveWaitlistRescheduleScenario.cs # Join, waitlist, promotion, leave, reschedule, notifications
+    ├── DatabaseAssertions.cs                # Query PostgreSQL and seed fake participants
+    ├── RunnerConfig.cs                      # Configuration model
+    ├── .env.example                         # Required environment variables
+    ├── .gitignore                           # Ignore .env and session files
+    └── packages.lock.json                   # Restored lock file for the runner project
 ```
 
 ## Install dependencies
@@ -109,7 +112,9 @@ The runner logs in to a real Telegram user account, creates a supergroup, invite
 - `test_dashboard_authenticates_and_shows_groups`  
   Builds a valid Mini App initData payload, posts it to `/auth/telegram-webapp`, and verifies that the Blazor home page renders the authenticated greeting.
 - `test_dashboard_session_edit_flow`  
-  Seeds a player, group, and session directly in PostgreSQL, opens the group details page, clicks through to the session editor, changes the title, and asserts the updated title appears on the page.
+  Seeds a player, group, and session directly in PostgreSQL, opens the group details page, clicks through to the session editor, changes the title, join link, max players and publication mode, asserts the updated values appear on the page, and verifies the persisted database state.
+- `test_dashboard_session_delete_flow`  
+  Seeds a session, opens the group details page, confirms the deletion dialog, asserts the session disappears from the dashboard, and verifies the session was removed from PostgreSQL.
 
 ## What the MTProto runner currently covers
 
@@ -117,13 +122,19 @@ The runner logs in to a real Telegram user account, creates a supergroup, invite
 - Create a supergroup (`Channels_CreateChannel` with `megagroup: true`).
 - Resolve a bot by username and invite it to the group.
 - Send `/start` to the bot inside the group and wait for any reply.
+- Walk `/newsession` from start to published schedule message.
+- Join/leave a session via inline buttons and assert the database state.
+- Join into a waitlist when the active roster is full (using a seeded fake participant).
+- Manually promote a waitlisted player via `/listsessions` and verify promotion.
+- Leave an active session and verify automatic promotion of the next waitlisted player.
+- Initiate a reschedule, propose 2-3 time options, vote, and wait for the background deadline service to apply the new time.
+- Exercise T-24h RSVP confirmation and T-5m join-link reminders by time-travelling `sessions.scheduled_at` from the runner (database-level time-mock).
 - Delete the test supergroup after the scenario (cleanup).
-- Send messages/commands and read recent messages.
-- Wait for a bot reply.
 
 ## Notes
 
 - Authentication is mocked using `helpers/telegram_init_data.py`, which mirrors `GmRelay.Shared.Telegram.TelegramAuthPayloadBuilder`.
 - The Web instance validates HMAC-SHA256 with the same bot token, so the test payload is indistinguishable from a real Telegram Mini App payload.
 - The runner project is intentionally **not** included in `GM-Relay.slnx` so it does not participate in CI builds or Native AOT trimming.
+- The Telegram lifecycle scenario uses **one real test account** plus fake participants seeded directly into PostgreSQL, and a **database-level time-mock** (`UPDATE sessions SET scheduled_at = ...`) so 24-hour and 5-minute reminders fire in minutes instead of hours. This is the locally-runnable approach chosen for issue #149.
 - For headful debugging, change `headless=True` to `headless=False` in the dashboard test file.