Add adapter environment testing infrastructure

Introduce testEnvironment() on ServerAdapterModule with structured
pass/warn/fail diagnostics for all four adapter types (claude_local,
codex_local, process, http). Adds POST test-environment endpoint,
shared types/validators, adapter test implementations, and UI API
client. Includes asset type foundations used by related features.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/agents-runtime.md

@@ -59,6 +59,7 @@ For local adapters, set:
 - `timeoutSec` (max runtime per heartbeat)
 - `graceSec` (time before force-kill after timeout/cancel)
 - optional env vars and extra CLI args
+- use **Test environment** in agent configuration to run adapter-specific diagnostics before saving
 
 ## 3.4 Prompt templates
 
@@ -148,6 +149,10 @@ Typical failure causes:
 - prompt too broad or missing constraints
 - process timeout
 
+Claude-specific note:
+
+- If `ANTHROPIC_API_KEY` is set in adapter env or host environment, Claude uses API-key auth instead of subscription login. Paperclip surfaces this as a warning in environment tests, not a hard error.
+
 ## 9. Security and risk notes
 
 Local CLI adapters run unsandboxed on the host machine.

docs/specs/agent-config-ui.md

@@ -33,6 +33,7 @@ Follows the existing `NewIssueDialog` / `NewProjectDialog` pattern: a `Dialog` c
 | Field | Control | Default | Notes |
 |-------|---------|---------|-------|
 | Adapter Type | Chip popover (select) | `claude_local` | `claude_local`, `codex_local`, `process`, `http` |
+| Test environment | Button | -- | Runs adapter-specific diagnostics and returns pass/warn/fail checks for current unsaved config |
 | CWD | Text input | -- | Working directory for local adapters |
 | Prompt Template | Textarea | -- | Supports `{{ agent.id }}`, `{{ agent.name }}` etc. |
 | Bootstrap Prompt | Textarea | -- | Optional, used for first run (no existing session) |