Merge branch 'web2-todo' into feat/todo-multi-in-progress

Stack the parallel-in_progress change on the web todo display (#497): the
GUI is now the surface where several active items are visible, so the two
land as a chain rather than colliding on tool-todo at merge time.

Conflicts combined rather than resolved to one side: tool-todo keeps this
branch's parallel-allowing validation AND web2-todo's additionalProperties
unknown-key rejection, in src/index.ts and both README sides; the spec
drops web2-todo's 'two in_progress' rejection case and keeps its unknown-key
case; the two headless advanced-toolchain session fixtures keep this
branch's parallel transcripts.

examples/acp-agent/tests/snapshots/advanced-toolchain/system-prompt.expected.md

@@ -162,7 +162,7 @@ interface ToolArgsMap {
       content: string;
       /** pending (not started) | in_progress (now) | completed (done). */
       status: "pending" | "in_progress" | "completed";
-    } & Record<string, JsonValue>)[];
+    })[];
   } & Record<string, JsonValue>;
   /** Update the exact current goal revision. edit, pause, and resume require a direct top-level human request. During an automatic continuation of the current goal, complete and blocked are also allowed. blocked is rejected before the configured minimum round count; the model remains responsible for judging that the same condition persisted across those rounds and must explain it in blocked_reason. */
   update_goal: {

examples/acp-agent/tests/snapshots/advanced-toolchain/tool-schemas.expected.json

@@ -366,7 +366,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",

examples/acp-agent/tests/snapshots/both-mode-turn/system-prompt.expected.md

@@ -145,7 +145,7 @@ interface ToolArgsMap {
       content: string;
       /** pending (not started) | in_progress (now) | completed (done). */
       status: "pending" | "in_progress" | "completed";
-    } & Record<string, JsonValue>)[];
+    })[];
   } & Record<string, JsonValue>;
   /** Update the exact current goal revision. edit, pause, and resume require a direct top-level human request. During an automatic continuation of the current goal, complete and blocked are also allowed. blocked is rejected before the configured minimum round count; the model remains responsible for judging that the same condition persisted across those rounds and must explain it in blocked_reason. */
   update_goal: {

examples/acp-agent/tests/snapshots/both-mode-turn/tool-schemas.expected.json

@@ -309,7 +309,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",

examples/acp-agent/tests/snapshots/code-mode-turn/system-prompt.expected.md

@@ -145,7 +145,7 @@ interface ToolArgsMap {
       content: string;
       /** pending (not started) | in_progress (now) | completed (done). */
       status: "pending" | "in_progress" | "completed";
-    } & Record<string, JsonValue>)[];
+    })[];
   } & Record<string, JsonValue>;
   /** Update the exact current goal revision. edit, pause, and resume require a direct top-level human request. During an automatic continuation of the current goal, complete and blocked are also allowed. blocked is rejected before the configured minimum round count; the model remains responsible for judging that the same condition persisted across those rounds and must explain it in blocked_reason. */
   update_goal: {

examples/acp-agent/tests/snapshots/code-mode-workspace-context/system-prompt.expected.md

@@ -145,7 +145,7 @@ interface ToolArgsMap {
       content: string;
       /** pending (not started) | in_progress (now) | completed (done). */
       status: "pending" | "in_progress" | "completed";
-    } & Record<string, JsonValue>)[];
+    })[];
   } & Record<string, JsonValue>;
   /** Update the exact current goal revision. edit, pause, and resume require a direct top-level human request. During an automatic continuation of the current goal, complete and blocked are also allowed. blocked is rejected before the configured minimum round count; the model remains responsible for judging that the same condition persisted across those rounds and must explain it in blocked_reason. */
   update_goal: {

examples/acp-agent/tests/snapshots/escalation-approved/tool-schemas.expected.json

@@ -288,7 +288,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",

examples/acp-agent/tests/snapshots/lsp-definition/tool-schemas.expected.json

@@ -325,7 +325,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",

examples/acp-agent/tests/snapshots/pty-tools/tool-schemas.expected.json

@@ -417,7 +417,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",

examples/acp-agent/tests/snapshots/session-query-spill/tool-schemas.expected.json

@@ -492,7 +492,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",

examples/acp-agent/tests/snapshots/skill-load/tool-schemas.expected.json

@@ -288,7 +288,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",

examples/acp-agent/tests/snapshots/text-turn/tool-schemas.expected.json

@@ -288,7 +288,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",

examples/acp-agent/tests/snapshots/workspace-context/tool-schemas.expected.json

@@ -288,7 +288,7 @@
             "description": "The COMPLETE task list, replacing any previous list.",
             "items": {
               "type": "object",
-              "additionalProperties": true,
+              "additionalProperties": false,
               "properties": {
                 "content": {
                   "type": "string",