feat: add interactive VT and workspace command plane

docs/decisions/0004-runtime-actor-owns-each-pty.md

@@ -16,9 +16,10 @@ arrives. Process-local session IDs are correlation IDs only; durable IDs are
 assigned by the persisted runtime protocol later.
 
 Runtime events contain ordered raw PTY bytes. The UI spike may line-frame plain
-fixture output for display, but ANSI/VT parsing, screen state, cursor behavior,
-scrollback, and terminal input modes belong to `lumbridge-terminal`. The UI must
-not infer terminal semantics from raw strings.
+fixture output for deterministic surfaces, but the live pane sends bytes through
+`lumbridge-terminal`. ANSI/VT parsing, screen state, cursor behavior, scrollback,
+and terminal input modes never belong to the runtime actor or UI. The UI must not
+infer terminal semantics from raw strings.
 
 Dropping the UI-side actor disconnects its bounded channels, releases an actor
 blocked by event backpressure, terminates the process group through

docs/decisions/0005-terminal-engine-boundary.md

@@ -0,0 +1,24 @@
+# 0005: Terminal semantics stay behind a Lumbridge-owned contract
+
+Status: accepted for the first terminal slice.
+
+Lumbridge uses `alacritty_terminal` with default features disabled as its first
+VT state engine. The dependency is mature enough to cover substantially more
+terminal behavior than a new parser, but its types do not cross into runtime,
+storage, IPC, or UI APIs.
+
+`lumbridge-terminal` accepts ordered raw PTY bytes and exposes immutable
+Lumbridge snapshots containing cells, styles, colors, cursor, terminal modes,
+and sanitized title state. It owns terminal key and paste encoding. Protocol
+replies such as device-status responses return as bytes and enter the same
+bounded actor queue as all other PTY input, preserving ordering.
+
+Clipboard writes such as OSC 52 are disabled by default. Transcript-bearing
+snapshots deliberately omit `Debug`, and terminal titles are bounded and stripped
+of controls. A renderer may derive plain rows for a spike, but that is not the
+terminal model and must not become the persistence or automation contract.
+
+Adopting this engine is reversible: conformance fixtures target the Lumbridge
+contract, and no upstream application code is copied into this repository.
+Kitty keyboard/graphics behavior, OSC 8 links, mouse modes, IME, selection, and
+platform rendering remain explicit qualification work.

docs/decisions/0006-workspace-command-plane.md

@@ -0,0 +1,20 @@
+# 0006: Every workspace controller uses one typed command plane
+
+Status: accepted for implementation.
+
+Human UI, CLI automation, remote clients, and agents submit the same typed
+workspace commands. Stable request IDs make retries idempotent. Pane IDs, split
+ratios, surfaces, launch intents, and close dispositions are validated before
+state changes, and a multi-command setup plan is applied atomically. Reusing an
+ID with a different origin or command is a conflict, not a silent duplicate.
+
+Each request has an origin and an explicit Observe, Configure, or Execute grant.
+The command declares the minimum capability it needs. Creating or terminating a
+process requires Execute; layout-only changes require Configure. Launch intents
+refer to a user shell or an approved harness profile and working directory, not
+arbitrary executable arguments or secret values.
+
+This reducer is not an authorization bypass. The future IPC layer authenticates
+the caller and supplies its granted capability; the reducer rechecks it before
+mutation. Durable audit events record request and object identities, never
+terminal input, transcript content, provider keys, or pane titles by default.

docs/decisions/0007-optional-lumbridge-harness.md

@@ -0,0 +1,27 @@
+# 0007: Lumbridge Harness is optional, separate, and capability-scoped
+
+Status: accepted for architecture; implementation and fork policy pending.
+
+Lumbridge may distribute a separately versioned Lumbridge Harness for prompt
+refinement, trace analysis, recommendations, and agent coordination. The native
+Rust terminal workspace remains complete without it, and the Harness does not
+run inside the UI process.
+
+The captured DeepSeek Harness is an MIT-licensed and architecturally useful
+reference, but it is also an unaudited Node/TypeScript developer preview with a
+web client and broad native dependency closure. A maintained fork, if selected,
+lives in its own repository/process, preserves required notices, and exposes a
+small versioned protocol. Its React UI is not embedded in Lumbridge. We can later
+replace the implementation with a first-party Rust service without changing the
+desktop contract.
+
+Model access is provider-neutral and begins with OpenAI-compatible endpoints so
+development can use a self-hosted Spark/Qwen model or a user-selected service
+such as Cerebras. Endpoint credentials are opaque secret-store handles.
+
+Trace analysis is opt-in per workspace. The user chooses the trace projection
+and destination; local processing stays local, while hosted processing requires
+an explicit preview and consent. Suggestions and decision-shelf choices carry no
+authority. Any setup, launch, mutation, or autopilot action becomes a typed
+workspace plan and can use only the Observe, Configure, or Execute capability
+granted to that run.