docs(FR-2571): address PR #6631 review feedback (excl. model store)

Addresses review comments on PR #6631 (Allowed client IPs / login screenshots) across all 4 languages. Model-store items are intentionally deferred to a separate change.

Text edits:
- header: rewrite V2 API wording (both Allowed client IPs and Original password notes) to explicit version gating — 'Backend.AI 26.4.0 and later'
- vfolder §10.1: add clarification that the top-bar project is auto-selected for project folders
- vfolder: rewrite write_content description as a per-folder (vfolder) RBAC permission, not a storage-host setting (verified via FolderExplorerModal.tsx — reads vfolder_node.permissions)
- vfolder §10.3: describe folder rename as available only inside the detail drawer
- vfolder §10.7: remove empty 'Folder Categories' heading
- overview §3.3: add Project page row to the accessible-menu table

Screenshots recaptured (EN + copied to ja/ko/th):
- menu_collapse.png (Fig 7.2 sidebar — no customer-specific plugins)
- data_page.png (Fig 10.1 / folder list with Controls merged into Name)
- vfolder_create_modal.png (current folder-creation modal)
- rename_vfolder.png (rename inside folder detail drawer)
- move_to_trash.png (new Ant Design Modal, replacing Popconfirm)
- vfolder_delete_dialog.png (current Delete Forever modal)
- sessions_page.png (Fig 11.1 current Sessions page)
- launch_session_resource_2.png (Cluster Mode step)
- launch_session_data.png (Data & Storage step)

Remaining TODO: header.png Login Session Timer (dev env has enableExtendLoginSession=false; timer not visible without backend config change).

Applied identically across en/ko/ja/th with structural parity.

Author: nowgnuesLee

.claude/agents/docs-screenshot-capturer.md

@@ -130,6 +130,27 @@ Open the browser and log in:
 - Use `browser_snapshot` to find the correct `ref` for the element you want to capture
 - When UI has icon-only buttons, **always verify the button's accessible name** in the snapshot before clicking — e.g., "trash bin" vs download icon can look similar
 
+**Re-capture preflight (when overwriting an existing screenshot):**
+
+The filename of an existing screenshot encodes a contract about what it shows. Silently broadening the scope (e.g., turning a header strip into a full-page capture) breaks documentation that references it. Before overwriting any existing image:
+
+1. Inspect the previous version's dimensions and visual scope:
+   ```bash
+   git show main:packages/backend.ai-webui-docs/src/en/images/foo.png > /tmp/old.png
+   file /tmp/old.png   # note WIDTH x HEIGHT
+   ```
+2. Open `/tmp/old.png` and identify its scope:
+   - Header strip: very wide, ≤300 px tall (e.g., 2358×222) → use `ref` of `[data-testid="webui-header"]`
+   - Modal/dialog only: medium, no chrome (e.g., 988×804) → use `ref` of `.ant-modal-wrap .ant-modal` or `[role="dialog"]`
+   - Sidebar segment: narrow column → use `ref` of `.ant-layout-sider`
+   - Wizard step / panel: capture the specific panel `ref`, not the layout root
+   - Full page (~viewport × viewport): `fullPage: true` is acceptable
+3. After capture, sanity-check dimensions match the same order of magnitude as the old. If new dimensions differ by more than ~2× in either axis, you broke the framing — recapture with `ref`.
+
+**Anti-pattern observed in PR #6708**: `header.png` was 2358×222 (header strip) on `main`, recaptured as 2880×1800 (full viewport including sidebar + main content). The filename promised "header" but the new image showed everything. Always run the preflight above before overwriting.
+
+If the framing genuinely needs to change, **rename the file** to reflect the new scope (e.g., `header.png` → `top_bar_with_session_timer.png`) and update all markdown references — never silently broaden an existing image.
+
 ```
 .playwright-mcp/packages/backend.ai-webui-docs/src/en/images/{filename}.png  ← captured with English UI
 .playwright-mcp/packages/backend.ai-webui-docs/src/ko/images/{filename}.png  ← captured with Korean UI

packages/backend.ai-webui-docs/SCREENSHOT-GUIDELINES.md

@@ -61,6 +61,37 @@ Standards for capturing, naming, and maintaining screenshots in the Backend.AI W
 - Full-page captures are appropriate for page overview screenshots, but for feature-specific documentation, crop to the relevant area so users can clearly identify what is being described
 - Include just enough surrounding context for users to orient themselves
 
+### Match the Existing Screenshot's Framing (for re-captures)
+
+When **replacing an existing screenshot** (same filename), the new image MUST match the previous image's framing scope. The filename encodes a contract about what the image shows.
+
+**Before recapturing**, run the following preflight on the file you intend to replace:
+
+```bash
+# 1. Inspect the previous version's dimensions and visual scope
+git show main:path/to/images/foo.png > /tmp/old.png
+file /tmp/old.png        # note WIDTH x HEIGHT
+# 2. Open /tmp/old.png and identify:
+#    - Is it a header strip? (very wide, very short — e.g., 2358x222)
+#    - Is it a modal/dialog only? (medium, no chrome — e.g., 988x804)
+#    - Is it a sidebar segment? (narrow column — e.g., 1500x1098)
+#    - Is it a full page? (~viewport width × viewport height — e.g., 2880x1800)
+```
+
+Then capture the new screenshot at the **same scope**:
+
+| Old image scope | Capture method |
+|---|---|
+| Header strip (e.g., `header.png`) | `ref` of `header`/top-bar element only — never `fullPage: true` |
+| Modal/dialog only | `ref` of `.ant-modal-wrap .ant-modal` or `[role="dialog"]` |
+| Sidebar segment | `ref` of the sidebar element |
+| Page region (e.g., a step in a wizard) | `ref` of the specific panel, not the whole layout |
+| Full page overview | `fullPage: true` is acceptable |
+
+**Anti-pattern observed in PR #6708**: `header.png` was 2358×222 (header strip only) on `main`, recaptured as 2880×1800 (full viewport including sidebar + main content + breadcrumbs). The filename promises "header" but the new image shows everything. **Always run the preflight above before re-capturing.**
+
+If the framing genuinely needs to change (e.g., the feature now spans more of the page), update the filename to reflect the new scope (e.g., `header.png` → `top_bar_with_session_timer.png`) rather than silently broadening an existing image.
+
 ### Cleanup After Capture
 
 - **Always delete any resources created during screenshot capture** (folders, files, sessions, etc.)

packages/backend.ai-webui-docs/src/en/header/header.md

@@ -112,7 +112,7 @@ Each item has the following meaning. Enter the desired value and click the
 
 - **Full Name**: User's name (up to 64 characters).
 - **Original password**: Your current password. This field is shown only when
-  the server does not support the V2 user update API, and you must enter it
+  connecting to a server prior to Backend.AI 26.4.0, and you must enter it
   when setting a new password on such servers.
 - **New password**: New password (8 characters or more containing at least 1
   alphabet, number, and symbol). Click the eye icon to reveal the input.
@@ -126,8 +126,7 @@ Each item has the following meaning. Enter the desired value and click the
   you must enter an OTP code at login.
 
 :::note
-The **Allowed client IPs** field is available when the server supports the V2
-user update API.
+The **Allowed client IPs** field is available from Backend.AI 26.4.0 and later.
 :::
 
 :::note