docs: comprehensive 2-week sweep of feature/PR coverage gaps (#28497)

Catch the website docs up to two weeks of merged work (May 4 – May 18, 2026,
roughly 1,080 PRs). The audit found ~50 user-visible features that had landed
in code with no docs footprint, plus a handful of stale pages. This PR closes
every gap the scan turned up.

New pages
- user-guide/features/deliverable-mode.md — extension list, agent triggers,
  kanban_complete artifacts pattern, [[as_document]] override (PR #27813).
- developer-guide/web-search-provider-plugin.md — authoring guide modeled on
  image-gen-provider-plugin, covering brave_free / ddgs / etc. (PR #25448).

Providers / auth
- Rename "Alibaba Cloud" → "Qwen Cloud (Alibaba DashScope)" everywhere the
  display label shows up; provider id stays `alibaba` (PR #24835).
- Document OAuth refresh-token quarantine for xAI / MiniMax / Codex (PRs
  #28116 / #28118 / #28119).
- Document Nous JWT minting from refresh token + invalid-refresh quarantine
  + cross-profile shared token store (PRs #27663 / #19712).
- Add `## Microsoft Entra ID authentication (keyless)` section to
  azure-foundry guide — DefaultAzureCredential, RBAC, OpenAI + Anthropic
  routing details (PR #28101 / #9df9816da).
- Custom providers `api_mode` is now prompted-and-persisted, not just URL
  autodetected (PR #25068).
- Delegation honours `api_mode` + auto-detects anthropic_messages base URLs
  (PR #26824).
- `x_search` auto-enables when xAI credentials are present (PR #27376).
- Add `xAI Grok OAuth (SuperGrok)` row to providers headline table (PR
  #26534).
- NVIDIA NIM billing-origin header is set automatically (PR #26585).

Windows / installer
- `install.ps1`: document `-Commit <sha>` and `-Tag <v>` pin params plus
  the BOM-strip / git-retry hardening (PR #28169).
- Document Hermes Desktop thin installer + first-launch bootstrap (PR
  #27822).
- Document `dep_ensure` Windows bootstrap (PR #27845).
- Document install-method auto-detection (pip / git / homebrew / nixos) and
  the matching update command (PR #27843).

Gateway / messaging
- `/platform list|pause|resume` full description + circuit-breaker
  semantics (PR #26600).
- Slack / Matrix / Mattermost get parallel `allowed_channels` /
  `allowed_rooms` allowlist sections matching Telegram/Discord/DingTalk
  (PR #21251).
- Discord `allow_any_attachment` + `max_attachment_bytes` (config and env
  vars) (PR #27245).
- Discord clarify-choice button rendering (PR #25485).
- Telegram `guest_mode` @mention bypass for allowlisted groups (PR
  #22759).
- Telegram `notifications` mode (`important` vs `all`) (PR #22793).
- `[[as_document]]` skill / response directive for forcing
  document-style media delivery (PR #21210).

CLI / TUI
- `/new [name]` argument (PR #19637).
- `/subgoal` user-supplied criteria appended to `/goal` (PR #25449).
- `/exit --delete` flag confirmation prompts for destructive slash
  commands (PR #22687).
- Status-bar additions: ▶ N background indicator (PR #27175), context
  compression count (PR #21218), YOLO mode banner+statusbar warning (PR
  #26238).
- `display.timestamps` + `docker_extra_args` config keys (PR #23599).
- TUI collapsible startup banner sections (PR #20625).
- `HERMES_SESSION_ID` exported to tool subprocesses (PR #23847).

i18n
- Refresh display.language locale list from 8 → 16 (en, zh, zh-hant, ja,
  de, es, fr, tr, uk, af, ko, it, ga, pt, ru, hu) — matches
  `agent/i18n.py:SUPPORTED_LANGUAGES`.

Tools / features
- `vision_analyze` native-pixel passthrough for vision-capable callers,
  with auxiliary text-describer fallback (PR #22955).
- `session_search` rewrite to the single-shape tool (discovery / scroll /
  browse modes) (PRs #27590 / #27840).
- Clarify MCP transport scope: client supports stdio + SSE; embedded
  `hermes mcp serve` is stdio-only (PR #21227).
- Web search backends table: add Brave Search (free tier) and DDGS rows
  (PR #21337).
- ACP session-scoped edit auto-approval modes (PR #27862).
- Curator rename map in the user-visible per-run summary (PR #22910).
- Prompt caching feature page reference in features/overview.md — Claude
  cross-session 1-hour prefix cache on native Anthropic / OpenRouter /
  Nous Portal (PR #23828).
- Cron per-job profile parameter (PR #28124).
- `--no-skills` flag for `hermes profile create` (PR #20986).

Build
- Verified with `npm run build` in `website/`; both `en` and `zh-Hans`
  locales compile. Remaining broken-link/anchor warnings are pre-existing
  (`rl-training.md` from learning-path / overview; the
  zh-Hans translation lag the docs skill already calls out).

website/docs/user-guide/sessions.md

@@ -60,6 +60,9 @@ into chat.
 Use `/compress` when a session gets long, `/new` for a fresh thread, and
 `hermes sessions prune` only when you want to delete old ended sessions from
 storage. Compression reduces the active context; it is not a privacy delete.
+Pass a name to `/new` (e.g. `/new payments-refactor`) to set the new session's
+initial title up front — useful for finding it later with `/resume <name>` or
+in the `/sessions` picker.
 :::
 
 ### Session Sources
@@ -412,9 +415,9 @@ session_search()
 
 Returns recent sessions chronologically (titles, previews, timestamps). Useful when the user asks "what was I working on" without naming a topic.
 
-### FTS5 Query Syntax
+### FTS5 query syntax
 
-The search supports standard FTS5 query syntax:
+The keyword mode supports standard FTS5 query syntax:
 
 - Simple keywords: `docker deployment` (FTS5 defaults to AND)
 - Phrases: `"exact phrase"`
@@ -432,6 +435,8 @@ The agent is prompted to use session search automatically:
 
 > *"When the user references something from a past conversation or you suspect relevant prior context exists, use session_search to recall it before asking them to repeat themselves."*
 
+Typical triggers: "we did this before", "remember when", "last time", "as I mentioned", or any reference to a project/person/concept that isn't in the current window.
+
 ## Per-Platform Session Tracking
 
 ### Gateway Sessions