fix(session-notification): revert PR #543 and add proper notification plugin conflict detection (#575)

* revert: undo PR #543 changes (bun shell GC crash was misdiagnosed)

This reverts commit 4a38e70 (PR #543) and 2064568 (follow-up fix).

## Why This Revert

The original diagnosis was incorrect. PR #543 assumed Bun's
ShellInterpreter GC bug was causing Windows crashes, but further
investigation revealed the actual root cause:

**The crash occurs when oh-my-opencode's session-notification runs
alongside external notification plugins (e.g., @mohak34/opencode-notifier).**

Evidence:
- User removed opencode-notifier plugin → crashes stopped
- Release version (with original ctx.$ code) works fine when used alone
- No widespread crash reports from users without external notifiers
- Both plugins listen to session.idle and send concurrent notifications

The real issue is a conflict between two notification systems:
1. oh-my-opencode: ctx.$ → PowerShell → Windows.UI.Notifications
2. opencode-notifier: node-notifier → SnoreToast.exe

A proper fix will detect and handle this conflict gracefully.

Refs: #543, oven-sh/bun#23177, oven-sh/bun#24368
See: docs/CRASH_INVESTIGATION_TIMELINE.md (in follow-up commit)

* fix(session-notification): detect and avoid conflict with external notification plugins

When oh-my-opencode's session-notification runs alongside external
notification plugins like opencode-notifier, both listen to session.idle
and send concurrent notifications. This can cause crashes on Windows
due to resource contention between different notification mechanisms:
- oh-my-opencode: ctx.$ → PowerShell → Windows.UI.Notifications
- opencode-notifier: node-notifier → SnoreToast.exe

This commit adds:
1. External plugin detection (checks opencode.json for known notifiers)
2. Auto-disable of session-notification when conflict detected
3. Console warning explaining the situation
4. Config option 'notification.force_enable' to override

Known notification plugins detected:
- opencode-notifier
- @mohak34/opencode-notifier
- mohak34/opencode-notifier

This is the actual fix for the Windows crash issue previously
misdiagnosed as a Bun.spawn GC bug (PR #543).

Refs: #543

* docs: add crash investigation timeline explaining the real root cause

Documents the investigation journey from initial misdiagnosis (Bun GC bug)
to discovering the actual root cause (notification plugin conflict).

Key findings:
- PR #543 was based on incorrect assumption
- The real issue is concurrent notification plugins
- oh-my-opencode + opencode-notifier = crash on Windows
- Either plugin alone works fine

* fix: address review feedback - add PowerShell escaping and use existing JSONC parser

- Add back single-quote escaping for PowerShell soundPath to prevent command failures
- Replace custom stripJsonComments with existing parseJsoncSafe from jsonc-parser
- All 655 tests pass

---------

Co-authored-by: sisyphus-dev-ai <sisyphus-dev-ai@users.noreply.github.com>

src/config/schema.ts

@@ -238,6 +238,11 @@ export const BackgroundTaskConfigSchema = z.object({
   modelConcurrency: z.record(z.string(), z.number().min(1)).optional(),
 })
 
+export const NotificationConfigSchema = z.object({
+  /** Force enable session-notification even if external notification plugins are detected (default: false) */
+  force_enable: z.boolean().optional(),
+})
+
 export const OhMyOpenCodeConfigSchema = z.object({
   $schema: z.string().optional(),
   disabled_mcps: z.array(AnyMcpNameSchema).optional(),
@@ -255,6 +260,7 @@ export const OhMyOpenCodeConfigSchema = z.object({
   skills: SkillsConfigSchema.optional(),
   ralph_loop: RalphLoopConfigSchema.optional(),
   background_task: BackgroundTaskConfigSchema.optional(),
+  notification: NotificationConfigSchema.optional(),
 })
 
 export type OhMyOpenCodeConfig = z.infer<typeof OhMyOpenCodeConfigSchema>
@@ -272,5 +278,6 @@ export type DynamicContextPruningConfig = z.infer<typeof DynamicContextPruningCo
 export type SkillsConfig = z.infer<typeof SkillsConfigSchema>
 export type SkillDefinition = z.infer<typeof SkillDefinitionSchema>
 export type RalphLoopConfig = z.infer<typeof RalphLoopConfigSchema>
+export type NotificationConfig = z.infer<typeof NotificationConfigSchema>
 
 export { AnyMcpNameSchema, type AnyMcpName, McpNameSchema, type McpName } from "../mcp/types"