docs(README): update architecture diagram and enhance CLI/API tables for clarity

README.md

@@ -10,7 +10,7 @@ Convert **env**, **YAML**, **JSON**, and **INI** to and from Go `map[string]any`
 ## Architecture
 
 ```mermaid
-flowchart LR
+flowchart TB
   Sources["Sources\nbytes reader file URL process env"]
   Parser["Parser\ngodotenv yaml ini json"]
   Norm["keymap.Walk\nNormalizer"]
@@ -85,7 +85,7 @@ os.WriteFile("out.json", b, 0o644)
 ## CLI: `envc`
 
 | Command                                                            | Purpose                                                         |
-| --- | --- |
+| ------------------------------------------------------------------ | --------------------------------------------------------------- |
 | `envc convert --from yaml --to env --input - --output -`           | Convert stdin YAML to dotenv on stdout                          |
 | `envc get --from yaml --path service.name config.yaml`             | Print one path (dot-separated; segments normalized like codecs) |
 | `envc merge --from yaml --to json --output out.json a.yaml b.yaml` | Deep-merge multiple YAML files, emit JSON                       |
@@ -93,7 +93,7 @@ os.WriteFile("out.json", b, 0o644)
 ## API (all codecs)
 
 | Method                                          | Description                       |
-| --- | --- |
+| ----------------------------------------------- | --------------------------------- |
 | `New(opts...)`                                  | Construct codec                   |
 | `Map(ctx)`                                      | Merged `map[string]any`           |
 | `Unmarshal(dst)` / `UnmarshalContext(ctx, dst)` | Decode into struct (or map)       |
@@ -106,7 +106,7 @@ Shared options (each subpackage): `WithBytes`, `WithReader`, `WithFile`, `WithUR
 ## Cross-format mapping
 
 | Go                        | YAML                       | ENV                       |
-| --- | --- | --- |
+| ------------------------- | -------------------------- | ------------------------- |
 | `Service.SubService.Name` | `service.sub-service.name` | `SERVICE_SUBSERVICE_NAME` |
 
 INI uses dotted sections, e.g. `[service.subservice]` with `name=...`.
@@ -114,7 +114,7 @@ INI uses dotted sections, e.g. `[service.subservice]` with `name=...`.
 ## Related libraries
 
 | Module                                                    | Role           |
-| --- | --- |
+| --------------------------------------------------------- | -------------- |
 | [go-matrix-bot](https://github.com/eSlider/go-matrix-bot) | Matrix bots    |
 | [go-onlyoffice](https://github.com/eSlider/go-onlyoffice) | OnlyOffice API |
 | [go-ollama](https://github.com/eSlider/go-ollama)         | Ollama client  |