feat(hashline): change hashline_edit default from true to false

Hashline edit tool and companion hooks now require explicit opt-in
via `"hashline_edit": true` in config. Previously enabled by default.

- tool-registry: hashline edit tool not registered unless opted in
- create-tool-guard-hooks: hashline-read-enhancer disabled by default
- Updated config schema comment and documentation
- Added TDD tests for default behavior

src/plugin/tool-execute-before.test.ts

@@ -1,5 +1,6 @@
 const { describe, expect, test } = require("bun:test")
 const { createToolExecuteBeforeHandler } = require("./tool-execute-before")
+const { createToolRegistry } = require("./tool-registry")
 
 describe("createToolExecuteBeforeHandler", () => {
   test("does not execute subagent question blocker hook for question tool", async () => {
@@ -219,4 +220,54 @@ describe("createToolExecuteBeforeHandler", () => {
   })
 })
 
+describe("createToolRegistry", () => {
+  function createRegistryInput(overrides = {}) {
+    return {
+      ctx: {
+        directory: process.cwd(),
+        client: {},
+      },
+      pluginConfig: {
+        ...overrides,
+      },
+      managers: {
+        backgroundManager: {},
+        tmuxSessionManager: {},
+        skillMcpManager: {},
+      },
+      skillContext: {
+        mergedSkills: [],
+        availableSkills: [],
+        browserProvider: "playwright",
+        disabledSkills: new Set(),
+      },
+      availableCategories: [],
+    }
+  }
+
+  describe("#given hashline_edit is undefined", () => {
+    describe("#when creating tool registry", () => {
+      test("#then should not register edit tool", () => {
+        const result = createToolRegistry(createRegistryInput())
+
+        expect(result.filteredTools.edit).toBeUndefined()
+      })
+    })
+  })
+
+  describe("#given hashline_edit is true", () => {
+    describe("#when creating tool registry", () => {
+      test("#then should register edit tool", () => {
+        const result = createToolRegistry(
+          createRegistryInput({
+            hashline_edit: true,
+          }),
+        )
+
+        expect(result.filteredTools.edit).toBeDefined()
+      })
+    })
+  })
+})
+
 export {}