Update all READMEs to follow version-agnostic documentation standards

Documentation improvements:
- Add Available Tags sections to all image READMEs (ESP-IDF, PlatformIO, ESP-Matter)
- Remove specific version numbers throughout, use placeholders (<version>, <commit>)
- Remove Version Information tables with hardcoded versions
- Simplify root README Registry section (removed detailed tags, kept minimal)
- Use generic terms: Python (not 3.11), Ubuntu LTS (not 24.04), Unity (not 2.6.0)
- Update build argument examples to use <version> placeholders
- Change build arg defaults to 'see Dockerfile' instead of specific versions

Rationale:
- Follows documentation-standards.mdc rules for version handling
- Documentation stays accurate as versions update via build matrix
- Reduces maintenance burden (no need to update READMEs when versions change)
- Focuses on image capabilities, not specific versions
- Tag information is image-specific, not in root README

Tag structure documented:
- latest/stable (floating)
- <prefix>-v<version> (pinned, recommended for CI/CD)
- sha-<commit> (debugging/exact build reproduction)

Author: hacker-cb

README.md

@@ -202,6 +202,8 @@ Images are published to GitHub Container Registry (GHCR):
 - **ESP-Matter**: `ghcr.io/jethome-iot/jethome-dev-esp-matter`
 - **PlatformIO**: `ghcr.io/jethome-iot/jethome-dev-platformio`
 
+See individual image documentation for available tags and usage examples.
+
 ## Use Cases
 
 - **CI/CD**: Automated firmware builds in GitHub Actions, GitLab CI

images/esp-idf/README.md

@@ -31,10 +31,28 @@ This image extends the official Espressif ESP-IDF image with additional tools fo
 
 ## Quick Start
 
+### Available Tags
+
+| 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) |
+
+**Tag Recommendations:**
+- **Development**: Use `latest` for convenience
+- **CI/CD**: Use version tags (`idf-v<version>`) for reproducibility
+- **Debugging**: Use commit tags (`sha-<commit>`) to reproduce exact build
+
 ### Pull Image
 
 ```bash
+# Latest build
 docker pull ghcr.io/jethome-iot/jethome-dev-esp-idf:latest
+
+# Specific version (recommended for CI/CD)
+docker pull ghcr.io/jethome-iot/jethome-dev-esp-idf:idf-v<version>
 ```
 
 ### Build Your Project

images/esp-matter/README.md

@@ -1,6 +1,6 @@
-# ESP-Matter v1.4.2 Development Image
+# ESP-Matter Development Image
 
-Docker image for ESP32 Matter device development with ESP-Matter SDK v1.4.2. Built on our ESP-IDF image, it provides a complete environment for developing Matter-compatible smart home devices.
+Docker image for ESP32 Matter device development with ESP-Matter SDK. Built on our ESP-IDF image, it provides a complete environment for developing Matter-compatible smart home devices.
 
 ## Overview
 
@@ -9,15 +9,15 @@ This image extends the `jethome-dev-esp-idf` image with Espressif's ESP-Matter S
 ## What's Inside
 
 **Base Image:**
-- `jethome-dev-esp-idf:idf-v5.4.1` - Inherits all ESP-IDF tools
-  - ESP-IDF 5.4.1 with all ESP32 toolchains
+- `jethome-dev-esp-idf` - Inherits all ESP-IDF tools
+  - ESP-IDF with all ESP32 toolchains
   - QEMU emulation (Xtensa and RISC-V)
   - pytest, pytest-embedded, testing tools
-  - Python 3.12.3, Ubuntu 24.04 LTS
-  - Build tools: ccache, jq, vim, nano, rsync
+  - Python, Ubuntu LTS
+  - Build tools: ccache, jq
 
 **ESP-Matter SDK:**
-- ESP-Matter v1.4.2
+- ESP-Matter
 - ConnectedHomeIP SDK (Matter reference implementation)
 - Matter device libraries and clusters
 - Example applications (light, switch, bridge, etc.)
@@ -38,10 +38,30 @@ Host tools (chip-tool, chip-cert, ZAP) are **NOT included** in this image to kee
 
 ## Quick Start
 
+### Available Tags
+
+| 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) |
+
+**Tag Recommendations:**
+- **Development**: Use `latest` for convenience
+- **CI/CD**: Use version tags (`idf-v<idf-ver>-matter-v<matter-ver>`) for reproducibility
+- **Debugging**: Use commit tags (`sha-<commit>`) to reproduce exact build
+
+**Note**: Version tags include both ESP-IDF and ESP-Matter versions for full clarity.
+
 ### Pull Image
 
 ```bash
+# Latest build
 docker pull ghcr.io/jethome-iot/jethome-dev-esp-matter:latest
+
+# Specific version (recommended for CI/CD)
+docker pull ghcr.io/jethome-iot/jethome-dev-esp-matter:idf-v<idf-ver>-matter-v<matter-ver>
 ```
 
 ### Build Matter Example
@@ -252,31 +272,19 @@ docker build -t jethome-dev-esp-matter .
 
 ```bash
 docker build \
-  --build-arg BASE_IMAGE_TAG=idf-v5.4.1 \
-  --build-arg ESP_MATTER_VERSION=v1.4.2 \
+  --build-arg BASE_IMAGE_TAG=idf-v<version> \
+  --build-arg ESP_MATTER_VERSION=v<version> \
   -t jethome-dev-esp-matter .
 ```
 
 Available build arguments:
-- `BASE_IMAGE_TAG` - ESP-IDF base image tag (default: `idf-v5.4.1`)
-- `ESP_MATTER_VERSION` - ESP-Matter version tag (default: `v1.4.2`)
+- `BASE_IMAGE_TAG` - ESP-IDF base image tag (default: see Dockerfile)
+- `ESP_MATTER_VERSION` - ESP-Matter version tag (default: see Dockerfile)
 
 ### Multi-Platform Support
 
 This image is built for both **linux/amd64** and **linux/arm64** architectures. Docker automatically pulls the correct image for your platform.
 
-## Version Information
-
-| Component | Version | Notes |
-|-----------|---------|-------|
-| Base Image | jethome-dev-esp-idf:idf-v5.4.1 | Our ESP-IDF image |
-| ESP-IDF | 5.4.1 | From base image |
-| ESP-Matter | v1.4.2 | Matter SDK for ESP32 |
-| ConnectedHomeIP | Included as submodule | Matter reference implementation |
-| Python | 3.12.3 | From base image |
-| Ubuntu | 24.04 LTS | From base image |
-| QEMU | 9.0.0 | From base image |
-
 ## Notes
 
 **Host Tools Not Included**: chip-tool, chip-cert, and ZAP are not included in this image to keep size minimal. For testing and commissioning, use separate controller installations or Matter-compatible platforms (Apple Home, Google Home, etc.).

images/platformio/README.md

@@ -9,12 +9,12 @@ This image provides a ready-to-use PlatformIO environment with ESP32 platform su
 ## What's Inside
 
 **Base Environment:**
-- Python 3.11 slim (Debian Bookworm)
-- PlatformIO Core (latest)
+- Python slim (Debian)
+- PlatformIO Core
 
 **Pre-installed Platforms:**
-- `espressif32@6.11.0` - ESP32 platform (all chip variants)
-- `native@1.2.1` - Native platform for unit testing
+- `espressif32` - ESP32 platform (all chip variants)
+- `native` - Native platform for unit testing
 
 **Build Tools:**
 - build-essential (gcc, g++, make)
@@ -27,14 +27,32 @@ This image provides a ready-to-use PlatformIO environment with ESP32 platform su
 - jinja2 - Template engine
 
 **Testing:**
-- Unity 2.6.0 - Globally installed test framework
+- Unity - Globally installed test framework
 
 ## Quick Start
 
+### Available Tags
+
+| 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) |
+
+**Tag Recommendations:**
+- **Development**: Use `latest` for convenience
+- **CI/CD**: Use version tags (`pio-v<version>`) for reproducibility
+- **Debugging**: Use commit tags (`sha-<commit>`) to reproduce exact build
+
 ### Pull Image
 
 ```bash
+# Latest build
 docker pull ghcr.io/jethome-iot/jethome-dev-platformio:latest
+
+# Specific version (recommended for CI/CD)
+docker pull ghcr.io/jethome-iot/jethome-dev-platformio:pio-v<version>
 ```
 
 ### Build Your Project
@@ -219,34 +237,24 @@ docker build -t jethome-dev-platformio .
 
 ```bash
 docker build \
-  --build-arg PIO_VERSION=6.1.18 \
-  --build-arg ESP32_PLATFORM_VERSION=6.11.0 \
-  --build-arg NATIVE_PLATFORM_VERSION=1.2.1 \
-  --build-arg UNITY_VERSION=2.6.0 \
+  --build-arg PIO_VERSION=<version> \
+  --build-arg ESP32_PLATFORM_VERSION=<version> \
+  --build-arg NATIVE_PLATFORM_VERSION=<version> \
+  --build-arg UNITY_VERSION=<version> \
   -t jethome-dev-platformio .
 ```
 
 Available build arguments:
-- `PIO_VERSION` - PlatformIO Core version (default: 6.1.18)
-- `ESP32_PLATFORM_VERSION` - Espressif32 platform version (default: 6.11.0)
-- `NATIVE_PLATFORM_VERSION` - Native platform version (default: 1.2.1)
-- `UNITY_VERSION` - Unity test framework version (default: 2.6.0)
+- `PIO_VERSION` - PlatformIO Core version (default: see Dockerfile)
+- `ESP32_PLATFORM_VERSION` - Espressif32 platform version (default: see Dockerfile)
+- `NATIVE_PLATFORM_VERSION` - Native platform version (default: see Dockerfile)
+- `UNITY_VERSION` - Unity test framework version (default: see Dockerfile)
 - `PIO_ENVS` - Environments for pre-build (currently disabled)
 
 ### Multi-Platform Support
 
 This image is built for both **linux/amd64** and **linux/arm64** architectures. Docker automatically pulls the correct image for your platform.
 
-## Version Information
-
-| Component | Version | Notes |
-|-----------|---------|-------|
-| Base Image | Python 3.11 slim | Debian Bookworm |
-| PlatformIO Core | 6.1.18 | Latest stable release |
-| ESP32 Platform | 6.11.0 | Version 6.12.0 has compatibility issues |
-| Native Platform | 1.2.1 | For unit testing |
-| Unity Framework | 2.6.0 | Globally installed |
-
 ## License
 
 MIT License - see [LICENSE](../../LICENSE) file.