feat: New Template Library (#7062)

## Summary

Implement the new design for template library

## Changes

- What
  - New sort option: `Popular` and  `Recommended`
  - New category: `Popular`, leverage the `Popular` sorting
  - Support add category stick to top of the side bar 
- Support template customized visible in different platform by
`includeOnDistributions` field

### How to make `Popular` and `Recommended` work

Add usage-based ordering to workflow templates with position bias
correction, manual ranking (searchRank), and freshness boost.

New sort modes:
- "Recommended" (default): usage × 0.5 + searchRank × 0.3 + freshness ×
0.2
- "Popular": usage × 0.9 + freshness × 0.1

## Screenshots (if applicable)

New default ordering:

<img width="1812" height="1852" alt="Selection_2485"
src="https://github.com/user-attachments/assets/8f4ed6e9-9cf4-43a8-8796-022dcf4c277e"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7062-feat-usage-based-template-ordering-2bb6d73d365081f1ac65f8ad55fe8ce6)
by [Unito](https://www.unito.io)

Popular category:

<img width="281" height="283" alt="image"
src="https://github.com/user-attachments/assets/fd54fcb8-6caa-4982-a6b6-1f70ca4b31e3"
/>

---------

Co-authored-by: Yourz <crazilou@vip.qq.com>
Co-authored-by: GitHub Action <action@github.com>

docs/TEMPLATE_RANKING.md

@@ -0,0 +1,66 @@
+# Template Ranking System
+
+Usage-based ordering for workflow templates with position bias normalization.
+
+Scores are pre-computed and normalized offline and shipped as static JSON (mirrors `sorted-custom-node-map.json` pattern for node search).
+
+## Sort Modes
+
+| Mode           | Formula                                          | Description            |
+| -------------- | ------------------------------------------------ | ---------------------- |
+| `recommended`  | `usage × 0.5 + internal × 0.3 + freshness × 0.2` | Curated recommendation |
+| `popular`      | `usage × 0.9 + freshness × 0.1`                  | Pure user-driven       |
+| `newest`       | Date sort                                        | Existing               |
+| `alphabetical` | Name sort                                        | Existing               |
+
+Freshness computed at runtime from `template.date`: `1.0 / (1 + daysSinceAdded / 90)`, min 0.1.
+
+## Data Files
+
+**Usage scores** (generated from Mixpanel):
+
+```json
+// In templates/index.json, add to any template:
+{
+  "name": "some_template",
+  "usage": 1000,
+  ...
+}
+```
+
+**Search rank** (set per-template in workflow_templates repo):
+
+```json
+// In templates/index.json, add to any template:
+{
+  "name": "some_template",
+  "searchRank": 8,  // Scale 1-10, default 5
+  ...
+}
+```
+
+| searchRank | Effect                       |
+| ---------- | ---------------------------- |
+| 1-4        | Demote (bury in results)     |
+| 5          | Neutral (default if not set) |
+| 6-10       | Promote (boost in results)   |
+
+## Position Bias Correction
+
+Raw usage reflects true preference AND UI position bias. We use linear interpolation:
+
+```
+correction = 1 + (position - 1) / (maxPosition - 1)
+normalizedUsage = rawUsage × correction
+```
+
+| Position | Boost |
+| -------- | ----- |
+| 1        | 1.0×  |
+| 50       | 1.28× |
+| 100      | 1.57× |
+| 175      | 2.0×  |
+
+Templates buried at the bottom get up to 2× boost to compensate for reduced visibility.
+
+---