docs: add a library-first documentation set for the v1 interface

[David Koleczek (DavidKoleczek)]

Adds docs_v1/, documenting amplifier-agent as a library that hosts embed, with the CLI, HTTP face, and TypeScript SDK as surfaces built on it rather than as peers.

docs/ is unchanged.

The organizing rule

The library is the product. Every surface adds transport and presentation and no capability, in both directions: a surface that quietly resolves approvals, or drops an event it cannot render, is a weaker product rather than a thinner path to the same one.

CLI commands are documented next to the library calls that produce them, which makes the rule checkable. A command with no library equivalent is visible as a defect instead of passing as a convenience.

Structure

00-index                what it is, and how it differs from Amplifier App CLI
01-install              library first, then the CLI and SDK
02-quickstart           config in, agent out, one reply
03-configuration        every AgentConfig field
04-context-intelligence session recording and forwarding
05-interface            the complete public surface, one page per area
06-providers            per-provider credentials and models
07-surfaces             CLI, HTTP, TypeScript
08-development          end-to-end tests and evaluations

Interface decisions captured here

No capability negotiation. It presupposes divergence the wrapper rule forbids, and under exact protocol-version equality the two sides cannot differ. Forward-compatible parsing replaces it: wrappers ignore unknown fields and forward unknown event types unchanged. That is what lets the agent gain an event without every wrapper needing a release first.

Turn ids are outbound only. The agent assigns them. cancel() takes no argument, because a session runs one turn at a time and there is never ambiguity about which turn it applies to.

Version information is module-level, readable without a constructed agent. The reason to check a version is usually that create_agent is failing.

Session storage keeps the context-intelligence/ layout, so existing tooling reads a session directory without adaptation. The two record files carry distinct format identities so each reader refuses the file that is not its own.

Reviewing

05-interface/index.md lists every public name in one place and is the fastest way to see the whole surface. 00-index.md carries the boundary: what is deliberately excluded and why.

Per-provider detail pages under 06-providers/ are scaffolded and empty.