Make Relay runtime config-driven

[nahiyankhan]

Category: new-feature
User Impact: Agents can gather structured Relay context from either a Ghost fingerprint package or an explicit framework-owned Relay config.
Problem: Relay had grown from a simple path-based fingerprint helper into an agent contract, but the runtime still assumed a root .ghost package and made non-.ghost agent-framework contexts awkward.
Solution: Make ghost relay gather load Relay config first, let base.kind choose fingerprint-backed or request-only resolution, add structured Relay requests and request stack resolvers, and document JSON as the authoritative host-agent contract.

Validation:

• pnpm build: passed locally and in pre-push hook
• pnpm test: passed locally and in pre-push hook, 419 tests
• pnpm check: passed locally, in pre-commit, and in pre-push hook
• pnpm dump:cli-help: ran and manifest is in sync

Changeset: added as a minor change for new Relay config/request/context capabilities.

Ghost Review:

• node packages/ghost/dist/bin.js check --base origin/main: passed, 0 findings
• node packages/ghost/dist/bin.js review --base origin/main: generated advisory packet successfully; packet noted the diff was truncated at its default byte budget
• node packages/ghost/dist/bin.js review --base origin/main --include-memory: not run in final form because this branch's CLI rejects --include-memory

File changes

.changeset/relay-context-packets.md
Adds release note copy for Relay context JSON, structured requests, and config-driven runtime selection.

apps/docs/src/content/docs/cli-reference.mdx
Updates Relay CLI docs to describe JSON as the agent contract, --request, --request-stdin, --config, GHOST_RELAY_CONFIG, and request-only config usage.

apps/docs/src/content/docs/getting-started.mdx
Adds getting-started guidance for Relay JSON, structured requests, and base.kind: none configs.

apps/docs/src/generated/cli-manifest.json
Regenerates CLI help metadata after Relay command/help changes.

docs/fingerprint-format.md
Clarifies how Relay config can add context outside the canonical .ghost package without changing the fingerprint package model.

docs/generation-loop.md
Updates generation setup around Relay JSON, prompt-shaped requests, and config-selected runtimes.

docs/host-adapters.md
Documents host responsibilities for Relay JSON, request creation, GHOST_RELAY_CONFIG, and request-only configs.

docs/relay-configs-and-context.md
Adds the main Relay config/context guide covering config precedence, base runtimes, request schemas, stack resolvers, sections, and JSON contract semantics.

packages/ghost/src/cli.ts
Moves Relay command registration to the dedicated Relay command module.

packages/ghost/src/context/default-relay-config.ts
Adds the built-in default Relay config with fingerprint base semantics.

packages/ghost/src/context/projection.ts
Adds bounded projection of declared Relay sources into projectable context sections.

packages/ghost/src/context/relay-config-loader.ts
Loads Relay config by precedence: --config, GHOST_RELAY_CONFIG, discovered .ghost/relay.yml, then default config.

packages/ghost/src/context/relay-config.ts
Defines Relay config schema/types, base.kind, request resolvers, stack unit sources, and validation rules.

packages/ghost/src/context/relay-context.ts
Builds ghost.relay-context/v1 JSON with sections, extras, config base, request metadata, gaps, and trace.

packages/ghost/src/context/relay-modes.ts
Defines Relay modes and internal capability selection for projections.

packages/ghost/src/context/relay-request-input.ts
Reads Relay request files/stdin and folds positional targets into requests when needed.

packages/ghost/src/context/relay-request.ts
Defines and validates ghost.relay-request/v1.

packages/ghost/src/context/request-resolution.ts
Resolves structured requests against declared stack resolvers and projects ordered unit sources.

packages/ghost/src/context/request-stack-document.ts
Discovers and validates block.stack/v1-style stack files for request resolution.

packages/ghost/src/context/selected-context.ts
Adds the no-base-fingerprint gap kind used by request-only Relay results.

packages/ghost/src/relay-command.ts
Adds the Relay CLI command implementation with JSON/markdown output, --config, --request, --request-stdin, and advanced mode handling.

packages/ghost/src/relay-runtime-helpers.ts
Contains runtime helper logic for request synthesis, request source shaping, sparse selected context, and projection merging.

packages/ghost/src/relay.ts
Wires Relay gather into config-first runtime selection, fingerprint-backed gathers, request-backed gathers, and request-only gathers while preserving the ghost.relay.gather/v2 JSON contract.

packages/ghost/src/skill-bundle/SKILL.md
Updates installed skill guidance for Relay config paths and the generalized Relay gather command.

packages/ghost/src/skill-bundle/references/brief.md
Updates agent brief recipe to consume Relay JSON and handle base.kind: none request-selected sections/extras.

packages/ghost/src/skill-bundle/references/review.md
Updates review recipe with Relay request/config guidance.

packages/ghost/src/skill-bundle/references/schema.md
Documents Relay configs as an extension to, or opt-out from, the default fingerprint base.

packages/ghost/src/skill-bundle/references/verify.md
Updates verification recipe for Relay config and request-only results.

packages/ghost/test/cli.test.ts
Adds CLI coverage for Relay JSON contract, request input, request-only configs, env config, target synthesis, validation failures, help text, and skill recipes.

packages/ghost/test/public-exports.test.ts
Verifies public Relay exports include config/context/request schemas and request parsing.

packages/ghost/test/relay.test.ts
Adds Relay API coverage for context JSON, config discovery, config override, source projection, request stack resolution, and request gaps.

Screenshots/Demos: N/A, no visual surface changed.