feat(core): refuse a build phase no listener is wired for; ban expected/actual

[martin-fleck-at]

AstExtension and BuildPhasePass declared their phase as any DocumentState, and a registration at a phase the pipeline wires no listener for was accepted and never fired. Both now declare phase as a union of the wired phases, AstExtensionPhase and BuildPassPhase, each with an all() namespace that the pipeline wires its listeners from and that register refuses a value outside of, as IntegrityPhase already does. An error class declaring both expected and actual is read by vitest as an assertion failure; a new ast-grep rule, error-expected-and-actual, holds that over source and test trees, and conventions name it. conventions also gains the line for the existing connection-without-logger rule, so CONTRIBUTING can describe check:ast-grep as the rules conventions names.

Breaking changes

• AstExtension.state and BuildPhasePass.state are renamed to phase.
• phase is typed AstExtensionPhase or BuildPassPhase; a DocumentState-typed variable no longer assigns to it.
• The services' protected bucket members follow the field: phaseBuckets, phaseBucketsFor and getPhaseBucket, formerly state….
• A registration built outside the register call, in a const, a factory or an array, needs an AstExtension or BuildPhasePass annotation, or as const on phase; written inline it compiles as before.

Decisions and their cost

• Both registries, not the one the issue names. BuildPhasePass had the same hole and the same private wiring list; guarding one and filing the other would leave the class half fixed.
• phase, one word. IntegrityRule already says phase, the Langium hooks are onBuildPhase and onDocumentPhase, and DocumentState stays the name of what a phase is a value of. Cost: the rename above.
• A plain Error. The throw fires at construction and nothing reacts to it at runtime; a code would be surface for nobody, and the sibling integrity guard is plain.
• Any class body, source and test trees. vitest reads the pair as properties, whatever the class and wherever on the prototype chain they sit, and a test-only error with that pair breaks the reporting of the test that throws it. Interfaces describe records and are left out, as is a pair split across a hierarchy, which no single-file rule can see; the header lists both.
• Dispatch stays wide. extendNode, extendDocument and runPasses keep phase: DocumentState; an unwired phase only finds an empty bucket there, so narrowing them would be one more break with nothing behind it.
• BuildPassPhase, beside BuildPhasePass. BuildPhasePassPhase repeats the word, and BuildPassPhase reads as the phase of a build pass. The two are close in spelling, but one is the item interface and the other a union of enum values, so swapping them fails to compile rather than misbehaves.
• A quoted or computed name counts. ['expected'] creates the same runtime property, so the rule matches those forms; a static member is flagged too, since excluding it buys nothing.

How I know it works

• Disabling either guard reddens its refusal test; widening either phase type back to DocumentState reddens the types test with an unused @ts-expect-error.
• A class with both getters planted in errors.ts fails ast-grep scan; the rule's test file holds fifteen invalid and six valid shapes, including the parameter-property, quoted, computed, abstract, declared, accessor and no-heritage cases, and the hierarchy split as not flagged.

Part of #178.