Merge pull request #6747 from dotCooCoo/fix/plugin-grant-sealed-api

Plug-ins: only an approval records a grant, and installs need one

docs/plugins.md

@@ -231,6 +231,13 @@ capability model proposed for PhotoCraft plug-ins
   `VECTORCRAFT_NO_PREFS` set there is no store, and a `grant` accepted under the flag lasts for that session only.
   With `--allow-plugin-grants`, pass `hash` set to the `plugin.inspect` entry's `hash` so that the module installed is
   the one the user saw.
+- The approval protects against plug-ins and automation clients (MCP, scripts and CLI requests): none of them can
+  approve a module's permissions. VectorCraft's own code records a grant only after that approval and when it loads
+  `grants.json`, and installs a module that lists permissions only under a grant recorded for this very module,
+  also when it loads the Additional Plug-ins Folder. The approval does not protect against native code linked into
+  VectorCraft or against another program running as the same user, which can change the files in the `Plug-ins`
+  folder. `grants.json` is not signed, so such a program can add a grant to it. `--allow-plugin-grants` is a choice
+  the person starting a headless session makes.
 - **Replacing asks first.** When the file is another module than the plug-in installed with its id, or, with none
   installed, its id has settings and a cache in the `Plug-ins` folder, Install Plug-in… and File › Open show its id
   and SHA-256 and ask whether to install it in place of that plug-in, which gives it the settings and cache kept for

docs/target-app-parity.md

@@ -1693,6 +1693,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
 - **Filter plug-ins read type, images and symbol instances (G17, #4333):** a filter at plug-in API level 2 lists `inputs` (`type`, `image`, `symbolInstance`) with `doc.read` in its `permissions`, so installing it asks for approval, and is also given the selected objects of those kinds, read only: type with its runs, character and paragraph attributes (no text past 256 KiB or 4,096 runs or paragraphs, or 16 MiB of runs over the input), images with their size, color mode and, when embedded and at most 1 MiB in base64 (16 MiB over the input), their RGBA pixels (a CMYK image's through the working CMYK profile; never a linked file's), and symbol instances with their symbol and transform. The objects come in paint order from the bottom, and an image that reaches the decoder counts toward the 16 MiB of pixels even when decoding fails. Every object counts toward the input's half of the memory cap; one whose fields besides its pixels and runs don't fit fails the run naming it and its size, a path or compound path that doesn't fit fails it too, and so do more than 100,000 of these objects. Its output returns each as `{id}` or exactly as given; any change or omission is refused before the document changes. Filters without `inputs` get the same input as before, except that compound paths that clip a clip group and paths inside a group that clips one are left out for every filter. Regressions: `crates/plugins/src/objects/tests.rs`, `crates/plugins/src/manifest.rs`, `crates/engine/src/tests/plugins.rs`, `crates/engine/tests/plugin_fuzz.rs`. Scores and hours unchanged.
 - **Plug-in grants cover one module (G17):** a grant counts only for the module with the id and SHA-256 it records. A module that lists permissions and has other bytes under the same id needs a new approval, even with the same permissions: `plugin.inspect` reports `needsApproval`, `plugin.install` refuses it without `grant`, Install Plug-in… and File › Open ask again, and the plug-in store and plug-in folders skip it. A module with a missing or empty permissions list needs no grant; without the list, it gets its kind's implied permissions. A grant with a malformed hash covers nothing. Regressions: `crates/plugins/src/permissions.rs`, `crates/engine/src/tests/plugins.rs`, `crates/ui-egui/src/tests/plugins.rs`. Scores and hours unchanged.
 - **Plug-in approval needs a person (G17):** a plug-in's permissions and heavy budget are approved in a dialog that only a person can confirm: the control channel, MCP and injected input are refused, and `plugin.install` takes `grant` or `allowHeavy` only with that approval. `vectorcraft-cli mcp` and `run` refuse them unless started with `--allow-plugin-grants`. Regressions: `crates/engine/src/tests/plugins.rs`, `crates/ui-egui/src/tests/automation.rs`, `apps/vectorcraft-cli/tests/it/cli.rs`. Scores and hours unchanged.
+- **Only an approval records a plug-in grant (G17):** `vectorcraft_plugins::registry::grant` takes a `GrantToken`, which the engine makes after an approval and when it loads `grants.json`, and `registry::install`, `install_bytes` and folder loads refuse a module that lists permissions no recorded grant gives this very module (`Error::NeedsApproval`), leaving the plug-in under its id and the revision as they were. A module without `permissions`, or with an empty list, installs as before. `docs/plugins.md` says what the approval does not protect against (native code linked into the app, another program running as the same user, the unsigned `grants.json`). Regressions: `crates/plugins/src/registry.rs`, `crates/plugins/tests/grant_sites.rs`, `crates/engine/src/tests/plugins.rs`. Scores and hours unchanged.
 - **Plug-in approval waits before OK (G17):** the approval dialog's OK stays disabled until its question has been on screen in the focused window for half a second, VectorCraft's own value; a click, Enter, Space, or a press begun before then installs nothing, and the dialog stays open. The wait starts over for every new question, even one that reads the same, and when the window gets the focus back, so a question swapped in just before a click is not approved by it. Cancel works at once. Regressions: `crates/ui-egui/src/tests/plugins.rs`. Scores and hours unchanged.
 - **A plug-in with no permissions ends its id's grant (G17):** installing a module that lists no permissions under a granted id forgets the grant, in the process and in `grants.json`, so the formerly approved bytes need a new approval. Attaching a `Plug-ins` folder whose module for that id lists no permissions forgets it too, and plug-in folders forget the process's grant. A refused install leaves the grant. Regressions: `crates/engine/src/tests/plugins.rs`, `crates/engine/tests/plugin_safe_mode.rs`. Scores and hours unchanged.
 - **Plug-in commands (G17):** a filter or live effect may declare up to 32 `commands` (`{id, label, params?}`); each is the command `plugin.<id>.<command>` while the plug-in is installed, in a submenu named after the plug-in under Object › Plug-ins (Effect › Plug-ins for a live effect) whatever menu the manifest names, with its label escaped. Commands are recorded in actions, listed in Keyboard Shortcuts for the user to give a shortcut, and run through `run` and MCP with their parameters checked first (a command with parameters opens a dialog from its menu item or shortcut). A run uses the plug-in's permissions (a live effect with commands may also hold `doc.write` and `state`, and gets them without a `permissions` list), is one undo step named after the command, and on failure (a trap or an exhausted instruction budget) leaves the document and the undo history as they were with an error naming the plug-in and the command. For a command and for `plugin.run`, an `ids` that is not a list of object ids is an error rather than the selection. A malformed entry is refused by name when the module is installed. Regressions: `crates/plugins/src/manifest.rs`, `crates/plugins/src/permissions.rs`, `crates/engine/src/tests/plugins.rs`, `crates/engine/tests/plugin_fuzz.rs`, `crates/ui-egui/src/tests/plugins.rs`. Scores and hours unchanged.