feat(stalker): protocol-correct auth lifecycle (#1354)

CLAUDE.md

@@ -1111,6 +1111,16 @@ engine` (restart required) or
 - Stalker: `StalkerAccountInfoComponent` (`libs/portal/stalker/feature/src/lib/stalker-account-info/`), cached-first — renders the import-time `stalkerAccountInfo` snapshot instantly, then `StalkerAccountInfoService` refreshes, routing by the observed portal MODE rather than the URL shape (full mode: handshake+`get_profile`; simple mode: best-effort `account_info/get_main_info`, nested `js.account_info` envelope or flat fields), and re-routing when a lazy repair changes the mode mid-request. Details: `docs/architecture/stalker-portal.md` ("Account Info Dialog").
 - Dashboard source cards carry a passive subscription-expiry chip (amber within 7 days, error-toned once expired); account details remain behind ⋮ → Account info. `DashboardSourceExpiryService` (`libs/workspace/dashboard/data-access/`) gathers the facts: Xtream from `PortalStatusService.checkPortalStatusDetails()` (the switcher's cached status check, now carrying `exp_date`), Stalker from the persisted `stalkerAccountInfo` snapshot — it lives in the playlist payload, not on meta rows, so each Stalker source costs one memoized full-playlist read.
 
+**Stalker Session Authentication**:
+
+- Full portals authenticate through `StalkerSessionService` (`libs/portal/stalker/data-access/src/lib/stalker-session.service.ts`), a facade over `stalker-auth.api.ts` (handshake / `get_profile` / `do_auth` + the `authenticate()` orchestration), `stalker-watchdog.controller.ts`, `stalker-portal-error.ts` and `stalker-response-classification.ts`.
+- `get_profile`'s `js.status` decodes as: full profile/`0` = OK, `1` = blocked, `2` = login/password required → `do_auth` then `get_profile` with `auth_second_step=1` (only that retry sets it). Credentials come from the import dialog's username/password fields and are persisted so runtime re-auth can repeat `do_auth`. Status is read through a numeric coercion — portals stringify it.
+- Refusals throw `StalkerPortalError` (`login-required` / `login-rejected` / `blocked` / `auth-failed`) carrying the portal's markup-stripped `msg`/`block_msg` in `portalText`; the import dialog and the workspace context panel render it. Read it with `asStalkerPortalError()`, never `instanceof` in lazy-loaded code.
+- Auth failures are HTTP 200 + plain text (`Authorization failed.` / `Access denied.` / `Unauthorized request.`), classified at the transport boundary by `libs/shared/interfaces/src/lib/stalker-auth-failure.util.ts`; the Electron handler **returns** a `{stalkerAuthFailure}` marker rather than throwing, because `ipcRenderer.invoke` strips custom properties off rejections.
+- The handshake is idempotent, so `Playlist.stalkerToken` is re-presented and `get_profile` is skipped when it comes back unchanged (unless `not_valid` is set, or the persisted `stalkerSessionIdentity` no longer matches `stalkerSessionFingerprint(playlist)` — portal endpoint (origin **and** path) + identity + credentials; an edited endpoint, MAC or login must never inherit the previous session, and a token with no recorded fingerprint counts as unverified. The path is deliberate: discovery preserves tenant base paths, so `/tenant-a/server/load.php` and `/tenant-b/server/load.php` are different portals on one host and must not share a session). The advertised watchdog cadence is persisted alongside it (`stalkerWatchdogTimeout`/`stalkerTimeslot`) precisely because that reuse skips the response carrying it — and the skip only applies once the cadence is known, so a legacy token-only playlist profiles once instead of being stranded on the default. The *effective* cadence is stored, so stored absence means "never profiled" and nothing re-profiles on every start.
+- Watchdog: `get_events` immediately (`init=1`), then every `watchdog_timeout` s (default **120**, clamped 30–3600) offset by `timeslot`. Ping failures are logged only — a missed ping never invalidates auth, it only affects the portal's "online" reporting.
+- Full contract: `docs/architecture/stalker-portal.md` ("Session Authentication Lifecycle").
+
 **Favorites and Recently Viewed**:
 
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