refactor(engine): generalize and simplify code schema definition

[asrcpq]

Overview

Currently Code in schema is a fixed type, so all code fields must have identical allowed language list.

This PR adds const generics to define accepted code types optionally for some fields. For example, conditions in FeatureFilter should not take plain string literal types. This PR also updates schema to pass the accepted types to the frontend.

Example

Feature filter's condition. Before:

// per-action definitions:
"Code": {
  "type": "object",
  "required": ["type", "value"],
  "properties": {
    "type": { "$ref": "#/definitions/CodeType" },
    "value": { "type": "string" }
  }
},
"CodeType": {
  "type": "string",
  "enum": ["flowExpr", "string"]   // always ALL types — no per-field restriction
},

// field:
"expr": {
  "title": "Condition expression",
  "allOf": [{ "$ref": "#/definitions/Code" }]
}

Code definition repeated every action, also impossible to express acceptable codeTypes.

This PR:

"expr": {
  "title": "Condition expression",
  "type": "code",
  "codeTypes": ["flowExpr"]
}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 7.86%. Comparing base (070257c) to head (25283ec).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2126   +/-   ##
=====================================
  Coverage   7.86%   7.86%           
=====================================
  Files        224     224           
  Lines      37600   37600           
=====================================
  Hits        2956    2956           
  Misses     34391   34391           
  Partials     253     253           

Flag	Coverage Δ
api	7.86% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[Copilot]

Pull request overview

Refactors the Code schema definition in the engine: replaces the per-action JSON Schema Code/CodeType definitions with an inline custom schema fragment ({"type": "code", "codeTypes": [...]}), and introduces a const-generic Code<MASK> Rust type so that fields can restrict accepted code types at compile-time (e.g. FeatureFilter's condition expression now only accepts flowExpr). Custom Serialize/Deserialize/JsonSchema impls back the new representation. Generated schemas (per-locale + mdbook docs) and i18n files are updated accordingly, and the workspace version is bumped to 0.0.377.

Changes:

• New const-generic Code<MASK> with custom serde + non-referenceable JsonSchema emitting type: "code" and a filtered codeTypes list, plus deserialize-time validation against the mask.
• FeatureFilter.Condition.expr now uses Code<{ CodeType::FlowExpr as u32 }> to restrict to flowExpr only.
• Regenerated schema JSONs, mdbook docs, and i18n files to remove inline Code/CodeType definitions and inline the new representation.

Reviewed changes

Copilot reviewed 15 out of 16 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
engine/runtime/types/src/expr.rs	Adds const-generic Code<MASK>, manual serde + custom JsonSchema, removes Expr::compile.
engine/runtime/action-processor/src/feature/filter.rs	Uses Code<{ CodeType::FlowExpr as u32 }> for condition expressions.
engine/schema/actions.json (and _en/_es/_fr/_ja/_zh)	Regenerated schemas with inline type: "code"/codeTypes and removed Code/CodeType definitions.
engine/schema/i18n/actions/*.json	Removed obsolete Code entries from definitionI18n.
engine/docs/mdbook/src/action.md	Regenerated mdbook docs to match new schemas.
engine/Cargo.toml, engine/Cargo.lock	Workspace version bump to 0.0.377.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[n4to4]

👍