feat: detect OpenCode origin + activate PLANNOTATOR_ORIGIN override (#590)

* feat: detect OpenCode origin + activate PLANNOTATOR_ORIGIN override

Extend the origin detection chain in apps/hook/server/index.ts to recognize
OpenCode via `process.env.OPENCODE`, the stable runtime flag set by the
OpenCode binary (also sets OPENCODE_RUN_ID, OPENCODE_PID, OPENCODE_PROCESS_ROLE,
but OPENCODE=1 is the canonical detection flag).

Additionally, activate `PLANNOTATOR_ORIGIN` as an explicit override. The
comment in packages/server/index.ts already documented this variable, but
it was never actually read. It is now honored at the top of the detection
chain and validated against AGENT_CONFIG so only known origins take effect
— invalid values fall through to env-based detection.

Priority order after this change:
  PLANNOTATOR_ORIGIN > Codex > Copilot CLI > OpenCode > Claude Code (default)

Single-point fix: all five existing `detectedOrigin` usages (lines 405,
568, 694, 741, 999) pick up the new chain automatically. The `'opencode'`
origin key is already defined in packages/shared/agents.ts (AGENT_CONFIG),
complete with a UI badge — the detection chain was the last missing piece.

Closes the gap noted in packages/shared/agents.ts header comment:
"If detection is via environment variable, add it to the detection chain
in apps/hook/server/index.ts (detectedOrigin constant)".

* fix: remove stray project argument from getServerConfig calls

getServerConfig only accepts gitUser — the project argument was silently
ignored at runtime but fails the typecheck. Reverts the two call sites to
their correct single-argument form.

For provenance purposes, this commit was AI assisted.

---------

Co-authored-by: Michael Ramos <mdramos8@gmail.com>

Author: HeikoAtGitHub

apps/hook/server/index.ts

@@ -80,7 +80,7 @@ import { detectProjectName } from "@plannotator/server/project";
 import { hostnameOrFallback } from "@plannotator/shared/project";
 import { planDenyFeedback } from "@plannotator/shared/feedback-templates";
 import { readImprovementHook } from "@plannotator/shared/improvement-hooks";
-import type { Origin } from "@plannotator/shared/agents";
+import { AGENT_CONFIG, type Origin } from "@plannotator/shared/agents";
 import { findSessionLogsForCwd, resolveSessionLogByPpid, findSessionLogsByAncestorWalk, getLastRenderedMessage, type RenderedMessage } from "./session-log";
 import { findCodexRolloutByThreadId, getLastCodexMessage } from "./codex-session";
 import { findCopilotPlanContent, findCopilotSessionForCwd, getLastCopilotMessage } from "./copilot-session";
@@ -140,10 +140,21 @@ const shareBaseUrl = process.env.PLANNOTATOR_SHARE_URL || undefined;
 const pasteApiUrl = process.env.PLANNOTATOR_PASTE_URL || undefined;
 
 // Detect calling agent from environment variables set by agent runtimes.
-// Priority: Codex > Copilot CLI > Claude Code (default fallback)
+// Priority:
+//   PLANNOTATOR_ORIGIN (explicit override, validated against AGENT_CONFIG)
+//   > Codex (CODEX_THREAD_ID)
+//   > Copilot CLI (COPILOT_CLI)
+//   > OpenCode (OPENCODE)
+//   > Claude Code (default fallback)
+//
+// To add a new agent, also add an entry to AGENT_CONFIG in
+// packages/shared/agents.ts (see header comment there).
+const originOverride = process.env.PLANNOTATOR_ORIGIN as Origin | undefined;
 const detectedOrigin: Origin =
+  (originOverride && originOverride in AGENT_CONFIG) ? originOverride :
   process.env.CODEX_THREAD_ID ? "codex" :
   process.env.COPILOT_CLI ? "copilot-cli" :
+  process.env.OPENCODE ? "opencode" :
   "claude-code";
 
 if (args[0] === "sessions") {

packages/server/index.ts

@@ -6,7 +6,10 @@
  * Environment variables:
  *   PLANNOTATOR_REMOTE - Set to "1"/"true" for remote, "0"/"false" for local
  *   PLANNOTATOR_PORT   - Fixed port to use (default: random locally, 19432 for remote)
- *   PLANNOTATOR_ORIGIN - Origin identifier ("claude-code" or "opencode")
+ *   PLANNOTATOR_ORIGIN - Explicit origin override; validated against AGENT_CONFIG
+ *                        in packages/shared/agents.ts. Supported values:
+ *                        "claude-code", "opencode", "codex", "copilot-cli",
+ *                        "gemini-cli", "pi".
  */
 
 import type { Origin } from "@plannotator/shared/agents";