Update documentation for image tags

- Remove redundant 'stable' tag from all image READMEs
- Keep only: latest, version-specific, and SHA tags
- Update tag tables in ESP-IDF, ESP-Matter, and PlatformIO READMEs
- Simplify tag strategy for better clarity

Author: hacker-cb

images/esp-idf/README.md

@@ -36,7 +36,6 @@ This image extends the official Espressif ESP-IDF image with additional tools fo
 | Tag Type | Example | Usage |
 |----------|---------|-------|
 | **Latest** | `latest` | Always points to newest build (floating) |
-| **Stable** | `stable` | Same as latest (semantic preference) |
 | **Version** | `idf-v<version>` | Pin to specific ESP-IDF base version (recommended for CI/CD) |
 | **Commit** | `sha-<commit>` | Pin to exact git commit (debugging) |
 

images/esp-matter/README.md

@@ -43,7 +43,6 @@ Host tools (chip-tool, chip-cert, ZAP) are **NOT included** in this image to kee
 | Tag Type | Example | Usage |
 |----------|---------|-------|
 | **Latest** | `latest` | Always points to newest build (floating) |
-| **Stable** | `stable` | Same as latest (semantic preference) |
 | **Version** | `idf-v<idf-ver>-matter-v<matter-ver>` | Pin to specific IDF + Matter combination (recommended for CI/CD) |
 | **Commit** | `sha-<commit>` | Pin to exact git commit (debugging) |
 

images/platformio/README.md

@@ -36,7 +36,6 @@ This image provides a ready-to-use PlatformIO environment with ESP32 platform su
 | Tag Type | Example | Usage |
 |----------|---------|-------|
 | **Latest** | `latest` | Always points to newest build (floating) |
-| **Stable** | `stable` | Same as latest (semantic preference) |
 | **Version** | `pio-v<version>` | Pin to specific PlatformIO version (recommended for CI/CD) |
 | **Commit** | `sha-<commit>` | Pin to exact git commit (debugging) |