docs: correct three false claims in backend architecture docs (#3001)

Co-authored-by: nova28 <17953305+nova28@users.noreply.github.com>
Co-authored-by: Carlos Florencio <carlosmflorencio@gmail.com>

AGENTS.md

@@ -248,7 +248,7 @@ Contract authority is intentionally split by implementation boundary: frontend a
 
 Runtime feature toggles add a SQLite-backed override tier managed through `Settings > System > Feature Toggles`. Effective values use this precedence: explicit environment variable > SQLite override > profile default. The typed runtime flag registry lives in `apps/backend/internal/runtimeflags/registry.go`; each registration owns the public metadata, environment variable, config reader, and config applier. Do not add parallel per-flag maps or switches.
 
-Profile selection: `KANDEV_E2E_MOCK=true` → `e2e`, `KANDEV_DEBUG_DEV_MODE=true` or `KANDEV_DEBUG_PPROF_ENABLED=true` → `dev`, otherwise `prod`. The Go dev launcher (`apps/backend/internal/launcher/dev.go`) and `apps/web/e2e/fixtures/backend.ts` set only the selector — they no longer hardcode the underlying values.
+Profile selection: `KANDEV_E2E_MOCK=true` → `e2e`, `KANDEV_DEBUG_DEV_MODE=true` → `dev`, otherwise `prod`. `KANDEV_DEBUG_PPROF_ENABLED=true` enables pprof behavior but does not select the `dev` profile on its own. The Go dev launcher (`apps/backend/internal/launcher/dev.go`) and `apps/web/e2e/fixtures/backend.ts` set only the selector — they no longer hardcode the underlying values.
 
 Stable operator startup settings have a separate typed source contract in
 `apps/backend/internal/common/config/catalog.go` and `source.go`. The catalog

apps/backend/AGENTS.md

@@ -168,7 +168,7 @@ Standalone agentctl is launched in its own process group so terminal Ctrl+C is h
 
 **Remote SSH executor platforms:** Treat supported remote OS/arch values as an end-to-end contract. Platform probe/normalization, lifecycle support checks, agentctl helper resolution, platform default shell, SSH readiness endpoints, frontend response types, and tests must stay aligned. Preserve raw unsupported platform details in user-facing errors, but use normalized values for supported-platform matching. Keep shell defaults platform-aware: Darwin defaults to `zsh`, Linux defaults to `bash`, unless an explicit shell is saved.
 
-**Remote SSH lifecycle:** Resolve and run remote preparation, then verify the canonical checkout, origin, and `HEAD` before starting agentctl. Retain the remote task directory in session state for stop/resume; terminal archive/delete/cascade cleanup runs over the live SSH connection before teardown, while ordinary stop and backend shutdown preserve the workspace.
+**Remote SSH lifecycle:** Resolve and run remote preparation, then verify the canonical checkout, origin, and `HEAD` before starting agentctl. Retain the remote task directory in session state for stop/resume. `SSHExecutor.StopInstance` never removes the task checkout at `<workdir_root>/tasks/<taskDirName>/` on any stop reason, including terminal (archive/delete/cascade). Automatic task-directory cleanup is out of scope for SSH v1 per `docs/specs/ssh-executor/spec.md`. Terminal stop reasons additionally run the executor profile's optional `cleanup_script` over the live SSH connection (empty on every seeded profile, so a no-op by default). Every stop reason except graceful backend shutdown kills the remote agentctl process and removes its per-session runtime directory.
 
 **Opt-in authentication & per-user scoping** (`internal/auth/`): auth is OFF by default; the global middleware (`auth/httpmw`, installed after CORS in `backendapp.buildHTTPServer`) then injects a synthetic admin identity for the pre-auth single user, so behavior is unchanged. Enablement is the `features.auth` runtime flag (`KANDEV_FEATURES_AUTH`, Settings > System > Feature Toggles) — the auth service derives its mode from `cfg.Features.Auth` (`disabled` / `setup` = flag-on-no-admin / `enabled` = flag-on-admin-exists); there is no separate `auth.mode` setting. When enabled, requests authenticate via the session cookie (base name `kandev_session`; the effective name is derived from the request host — port-scoped on a ported host via `internal/common/httpcookie`, plain on a default-port host) or a `kandev_pat_*` bearer token. Scoping rules:
 - **Identity travels in the request context** (`authn.IdentityFromContext`). No identity = internal caller (pollers, event bus, office schedulers) = unscoped. Synthetic identity = auth disabled = unscoped.

apps/backend/internal/agentctl/AGENTS.md

@@ -38,11 +38,10 @@ GitHub PR and GitLab MR URLs trigger backend association callbacks. Azure PR URL
 ## Adapter Model
 
 Protocol adapters in `server/adapter/transport/` normalize different agent CLIs:
-- `AgentAdapter` interface defines `Start()`, `Stop()`, `Prompt()`, `Cancel()`
-- Transports: `acp` (Claude Code), `codex` (OpenAI Codex), `opencode`, `shared`, `streamjson`
-- Top-level adapters: `CopilotAdapter` (GitHub Copilot SDK), `AmpAdapter` (Sourcegraph Amp)
+- `AgentAdapter` interface defines `Connect()`, `Initialize()`, `NewSession()`, `LoadSession()`, `Prompt()`, `Cancel()`, `Updates()`, `Close()`, among others
+- Transports: `acp` (all supported agent CLIs speak ACP), `shared` (cross-transport helpers). Only the ACP protocol is supported; non-ACP variants were removed in the ACP-first migration
 - `process.Manager` owns subprocess, wires stdio to adapter
-- Factory pattern in `server/adapter/factory.go` selects adapter by agent type
+- `NewAdapter` in `server/adapter/factory.go` selects the adapter by protocol (`agent.Protocol`), not by agent type; agent identity and CLI-specific config come from Go constructors in `internal/agent/agents/`, registered by `internal/agent/registry.Registry.LoadDefaults()`
 
 The `acp` transport is split by concern across `adapter_*.go` files: `adapter.go` (core/lifecycle), `adapter_session.go` (initialize/new/load/resume), `adapter_prompt.go` (prompt/cancel), `adapter_updates.go` (`session/update` notification fan-out), `adapter_tools.go` (`convertToolCallUpdate` / `convertToolCallResultUpdate` -> normalized payloads), `adapter_permissions.go`, and `adapter_helpers.go`. Agent-specific ACP extensions use the package-private `acpDialect` function table in `dialect.go`; keep observed wire translation in `dialect_<agent>.go`. Dialect hooks return normalized data or request descriptions and never receive `*Adapter` or execute RPCs. Shared capability normalization used by both live sessions and utility probes belongs in `internal/agentctl/acpcompat/`. Tool-call conversion lives in `adapter_tools.go`, not `adapter.go`. See ADR-0043.