docs(plugins): entity-class label convention; demo in template v2

- plugin-architecture.md: new "Entity class display labels (API v10)"
  section documenting the split (stable identity keys in XDATA, display
  labels in the plugin declaration), the live-loaded-plugin gating (missing,
  disabled, cap-excluded, failed, removed, or dead → bare native type), the
  "<Label> (<Native>)" display rule, that raw schema fields (`type`,
  `dxf_name`, `record_type`) and LIST are unchanged, and that the label is
  display-only. `plugin.toml` deliberately does not carry the table: it is
  the pre-load discovery file and labels must activate on live manifests.
- Template v2 demonstrates the whole convention: declares
  `SURVEY-CLASS:POINT -> "Survey Point"` and stamps the identity key in
  MARK_FIRST_SURVEY_POINT, so marked points show as "Survey Point (Point)"
  while the plugin is loaded. plugin.toml's api_version is bumped to 10 (keep
  in sync with ApiVersion::CURRENT) with a NOTE on where the class table
  lives. DESIGN.md documents the flow.
- Template v2's stale `acadrust` pin (8a28c21, predating the host's codec
  bump to 278c49a) is realigned with the host's pin: without it the template
  no longer compiles on main — its `acadrust::EntityType` and the host
  re-exports are distinct types when the revisions disagree (verified the
  same four type errors occur before and after this feature's template edit).
- changelogs/unreleased.md entry (Plugins section).

changelogs/unreleased.md

@@ -52,6 +52,9 @@
 * **Selection Event Streaming:** Automation clients now receive real-time selection change notifications. *(Contributed by [@YsDirector](https://github.com/YsDirector))*
 * **Host API v8:** Added name-addressed `XRecord` CRUD operations on `HostApi`. *(Contributed by [@schoeller](https://github.com/schoeller))*
 
+#### Plugins
+* **Plugin-Declared Entity Class Labels (Host API v10):** Plugins can now give their XDATA-stamped entities human type names: the plugin stamps a stable class-identity key (e.g. `CVIFC-CLASS:LINE`) into entity XDATA and declares key → label mappings via the new `BuiltinPlugin::entity_classes()` manifest accessor; while the plugin is loaded, the Properties panel title and the records/automation `display_type` field show `<Label> (<Native>)` (e.g. "Linear Element (Line)"). Labels are display-only, resolved live from the loaded plugin set (not installed / disabled / dead process → bare native type), and never round-trip the drawing — identity keys do, so labels stay plugin-localizable without rewriting files. Raw schema fields (`type`, `dxf_name`, `record_type`) and the `LIST` command output are unchanged. *(Contributed by [@schoeller](https://github.com/schoeller))*
+
 ---
 
 ### 🐛 Bug Fixes

docs/plugin-architecture.md

@@ -134,6 +134,7 @@ pub trait BuiltinPlugin: Send + Sync {
     fn ribbon(&self) -> Box<dyn CadModule>;            // the ribbon tab
     fn dispatch(&self, host: &mut dyn HostApi, cmd: &str) -> bool;
     fn on_load(&mut self, host: &mut dyn HostApi) {}
+    fn entity_classes(&self) -> Option<&'static EntityClasses> {} // API v10
 }
 ```
 
@@ -296,6 +297,57 @@ Store domain data on entities as XDATA (under your `xdata_apps` ids), not in a
 side database, so it round-trips through DWG/DXF. `write_record` also registers
 the APPID. Document your schemas in the plugin's own `PLUGIN.md`.
 
+### Entity class display labels (API v10)
+
+A plugin can give its XDATA-stamped entities human type names in the host UI.
+The split between *identity* (in the drawing) and *labels* (in the plugin) is
+the point:
+
+- **Identity** — the plugin stamps one string value into an entity's XDATA
+  record: `"<class_prefix><KEY>"`, e.g. `"CVIFC-CLASS:LINE"`. The key is
+  stable, meaningless to the host, and round-trips the DWG/DXF verbatim.
+- **Labels** — the plugin declares a table and exposes it through
+  `BuiltinPlugin::entity_classes()`:
+
+```rust
+use ocs_plugin_api::manifest::EntityClasses;
+
+static ENTITY_CLASSES: EntityClasses = EntityClasses {
+    app_id: "CVIFC",                    // one of the manifest's xdata_apps
+    class_prefix: "CVIFC-CLASS:",
+    labels: &[
+        ("LINE", "Linear Element"),
+        ("CIRCULARARC", "Circular Arc Element"),
+    ],
+};
+
+impl BuiltinPlugin for MyPlugin {
+    fn entity_classes(&self) -> Option<&'static EntityClasses> {
+        Some(&ENTITY_CLASSES)
+    }
+    // ...
+}
+```
+
+The host resolves them at display time only: the single-entity Properties
+panel title becomes `"Linear Element (Line)"`, and the records/automation
+`display_type` field takes the same form. The rule is display-only — a label
+never governs behavior, and the raw schema fields (`type`, `dxf_name`,
+`record_type`, the command-line `LIST` output) stay native so existing scripts
+and filters keep working.
+
+**Gating.** Declarations are consulted through the live plugin manager, never
+cached: a plugin that is not installed, is disabled, is excluded by
+`OCS_PLUGIN_MAX_API_VERSION`, failed at load, has been removed, or whose
+process has died contributes nothing — its entities display as their bare
+native type ("Line"), immediately, with no re-open needed. An `app_id` claimed
+by more than one loaded plugin resolves through the first-loaded declaration;
+later duplicates are ignored (debug-logged). A class key that is empty,
+missing from the table, or mapped to an empty label falls back to the native
+type. Because labels are display text resolved from the loaded plugin, they
+are plugin-localizable and fixable without rewriting drawings — and
+`plugin.toml` (the pre-load discovery file) deliberately does not carry them.
+
 ---
 
 ## Building & distribution

docs/plugin-template-v2/Cargo.toml

@@ -12,4 +12,8 @@ crate-type = ["cdylib"]
 
 [dependencies]
 ocs_plugin_api = { path = "../../crates/ocs_plugin_api", features = ["host"] }
-acadrust = { git = "https://github.com/HakanSeven12/opencadcodec.git", rev = "8a28c21" }
+# Must match the host's opencadcodec pin exactly (its Cargo.toml's `codec`
+# entry): the plugin's entities and the host's re-exports are the same types
+# only when both resolve the same revision. The registration `rustc` /
+# `acadrust_source` gates enforce this at load time too.
+acadrust = { package = "opencadcodec", git = "https://github.com/HakanSeven12/opencadcodec.git", rev = "278c49a" }

docs/plugin-template-v2/DESIGN.md

@@ -20,7 +20,7 @@ rather than a runtime dependency of the host.
 |---|---|
 | `COUNT_SURVEY_POINTS` | Count point entities on the `SURVEY` layer via `document_reader()`. |
 | `ADD_SURVEY_POINT` | Add a new point entity on the `SURVEY` layer via `host.add_entity()`. |
-| `MARK_FIRST_SURVEY_POINT` | Read the first `SURVEY` point and mark it with an XDATA record. |
+| `MARK_FIRST_SURVEY_POINT` | Read the first `SURVEY` point and mark it with an XDATA record (including the `SURVEY-CLASS:POINT` identity key). |
 | `COUNT_MARKED_SURVEY_POINTS` | Count `SURVEY` points that carry the `SURVEYMARK` XDATA record. |
 
 ---
@@ -48,6 +48,24 @@ Each [`ReaderEntity`](ocs_plugin_api::host::ReaderEntity) exposes the entity
 
 This is the primary read→write round-trip pattern the template demonstrates.
 
+### Entity class display labels
+
+The template also demonstrates the entity-class label convention (API v10):
+
+- the plugin declares `ENTITY_CLASSES` and exposes it through
+  `BuiltinPlugin::entity_classes()`: app `SURVEYMARK`, prefix
+  `SURVEY-CLASS:`, and key → label mappings;
+- `MARK_FIRST_SURVEY_POINT` stamps a `SURVEY-CLASS:POINT` string value into
+  the point's XDATA alongside the existing marker value.
+
+While the plugin is loaded, the host shows marked points as
+"Survey Point (Point)" in the Properties panel title and in the
+`display_type` field of the records/automation APIs; without the plugin they
+are plain "Point" again. Only the stable key round-trips the drawing — the
+label text lives in the plugin and can be reworded or localized without
+touching saved files. The label is display-only: it never governs snapping,
+selection, or any other behavior.
+
 ### Ribbon integration
 
 The plugin registers one ribbon module (`SurveyTools`) with one group

docs/plugin-template-v2/plugin.toml

@@ -8,7 +8,9 @@ license = "GPL-3.0-only"
 repository = "your-account/your-plugin-repo"
 
 [opencad]
-api_version = 5
+# Keep in sync with the Rust manifest's `ApiVersion::CURRENT` — this is the
+# pre-load gate; the runner also checks the compiled-in symbol.
+api_version = 10
 # Replace both placeholders in the packaging step. The v1 template's
 # release workflow contains a working example.
 rustc_version = "__RUSTC_VERSION__"
@@ -21,3 +23,7 @@ command_prefixes = [
     "COUNT_MARKED_SURVEY_POINTS",
 ]
 xdata_apps = ["SURVEYMARK"]
+# NOTE: the plugin's entity-class display labels (see `ENTITY_CLASSES` in
+# src/lib.rs) travel on the registered manifest over IPC, not in this file —
+# they only apply while the plugin is loaded, so plugin.toml (the pre-load
+# discovery file) deliberately does not carry them.

docs/plugin-template-v2/src/lib.rs

@@ -8,7 +8,7 @@ use acadrust::xdata::{ExtendedDataRecord, XDataValue};
 use acadrust::{EntityType, Handle};
 use ocs_plugin_api::export_plugin;
 use ocs_plugin_api::host::{BuiltinPlugin, HostApi, ReaderEntityKind};
-use ocs_plugin_api::manifest::{ApiVersion, PluginManifest};
+use ocs_plugin_api::manifest::{ApiVersion, EntityClasses, PluginManifest};
 use ocs_plugin_api::ribbon::{CadModule, IconKind, ModuleEvent, RibbonGroup, RibbonItem, ToolDef};
 
 static MANIFEST: PluginManifest = PluginManifest {
@@ -27,6 +27,18 @@ static MANIFEST: PluginManifest = PluginManifest {
     ],
 };
 
+/// Entity-class display labels (API v10): entities carrying a
+/// `SURVEY-CLASS:<key>` string in their SURVEYMARK XDATA display the mapped
+/// label (e.g. "Survey Point (Point)") in the host's Properties panel and
+/// `display_type` — *while this plugin is loaded*. The key is the only thing
+/// stored in the drawing; the label text lives here, so it can be reworded or
+/// localized without rewriting drawings.
+static ENTITY_CLASSES: EntityClasses = EntityClasses {
+    app_id: "SURVEYMARK",
+    class_prefix: "SURVEY-CLASS:",
+    labels: &[("POINT", "Survey Point")],
+};
+
 struct PluginTemplateV2;
 
 impl BuiltinPlugin for PluginTemplateV2 {
@@ -34,6 +46,12 @@ impl BuiltinPlugin for PluginTemplateV2 {
         &MANIFEST
     }
 
+    // API v10: expose the entity-class labels declared above. The default
+    // (not overriding this) declares none.
+    fn entity_classes(&self) -> Option<&'static EntityClasses> {
+        Some(&ENTITY_CLASSES)
+    }
+
     fn ribbon(&self) -> Box<dyn CadModule> {
         Box::new(TemplateModule)
     }
@@ -106,6 +124,11 @@ fn first_survey_point_handle(host: &mut dyn HostApi) -> Option<Handle> {
 fn mark_point(host: &mut dyn HostApi, handle: Handle) {
     let mut record = ExtendedDataRecord::new("SURVEYMARK");
     record.add_value(XDataValue::Integer32(1));
+    // Class-identity key for the entity-class labels declared above: the
+    // host shows marked points as "Survey Point (Point)" while this plugin is
+    // loaded, and as plain "Point" when it is not. Keys are stable identity —
+    // display text never goes into the drawing.
+    record.add_value(XDataValue::String("SURVEY-CLASS:POINT".to_string()));
     if host.write_record(handle, record) {
         host.push_info(&format!("Marked SURVEY point {handle}"));
     } else {