feat: task_completed signal — post-task skill capture (v0.3.2)

Adds an 11th signal type emitted when a run of work (between two
UserPromptSubmit events) crosses three quality gates:
  - >=5 tool calls (TASK_TOOL_MIN)
  - >=3 distinct tool kinds (TASK_DIVERSITY_MIN, filters single-tool
    sweeps like "wrote 5 files")
  - 0 correction signals during the run (filters tasks where the user
    pushed back; correction-during-task disqualifies the recipe)

Payload carries tool_count, tool_kinds, active_skills, active_agents
so the agent can cluster by sorted tool-kind tuple and route through
the existing skill-overlap rule (skill_new vs skill_edit).

Importantly: cross_session_evidence is FALSE on first occurrence,
so resulting skill_new proposals always queue for review — they only
auto-apply when the same multi-tool recipe recurs in a second session
(then the existing rubric kicks in). Post-task creation captures novel
patterns while preserving the rule "auto-apply requires cross-session".

Hook adds state fields: task_tool_count, task_tool_kinds, task_corrections.
All reset on UserPromptSubmit boundary and on session change.

Agent gets one new signal-types-table row and one clustering bullet
referencing the existing skill-overlap rule.

3 new tests (30 passed, 0 failed):
  - 5 tools + 5 kinds + 0 corrections fires task_completed
  - 5 tools + 1 kind (Edit only) does NOT fire (diversity gate)
  - 5 tools + 3 kinds + correction-on-closing-prompt does NOT fire

hooks/adam-observe.mjs

@@ -32,6 +32,8 @@ const CORRECTION_FREE_THRESHOLD = 5;
 const CLEAN_RECOVERY_WINDOW = 3;
 const STRUGGLE_TYPES = new Set(["tool_error_loop", "dead_end", "retry_loop"]);
 const ACTIVE_SKILLS_LOOKBACK = 10;
+const TASK_TOOL_MIN = 5;
+const TASK_DIVERSITY_MIN = 3;
 const STATE_MAX_BYTES = 1_000_000;
 
 function safeRead(path, fallback) {
@@ -133,6 +135,9 @@ function resetSessionLocal(state) {
   state.correctionFreeCounter = 0;
   state.recoveryWatch = null;
   state.tool_window = [];
+  state.task_tool_kinds = {};
+  state.task_tool_count = 0;
+  state.task_corrections = 0;
 }
 
 function ensureStateDefaults(state) {
@@ -149,6 +154,9 @@ function ensureStateDefaults(state) {
   if (typeof state.correctionFreeCounter !== "number") state.correctionFreeCounter = 0;
   if (state.recoveryWatch === undefined) state.recoveryWatch = null;
   if (!Array.isArray(state.activity_ring)) state.activity_ring = [];
+  if (!state.task_tool_kinds || typeof state.task_tool_kinds !== "object") state.task_tool_kinds = {};
+  if (typeof state.task_tool_count !== "number") state.task_tool_count = 0;
+  if (typeof state.task_corrections !== "number") state.task_corrections = 0;
 }
 
 function main() {
@@ -178,6 +186,7 @@ function main() {
         prev_file: last.file || null,
       });
       state.correctionFreeCounter = 0;
+      state.task_corrections += 1;
     } else {
       state.correctionFreeCounter += 1;
       if (state.correctionFreeCounter >= CORRECTION_FREE_THRESHOLD) {
@@ -190,6 +199,22 @@ function main() {
         state.correctionFreeCounter = 0;
       }
     }
+    // Evaluate prior task (work between previous UserPromptSubmit and this one).
+    const taskKinds = Object.keys(state.task_tool_kinds);
+    if (state.task_tool_count >= TASK_TOOL_MIN &&
+        taskKinds.length >= TASK_DIVERSITY_MIN &&
+        state.task_corrections === 0) {
+      appendJournal({
+        ts, session, cwd, type: "task_completed",
+        tool_count: state.task_tool_count,
+        tool_kinds: taskKinds,
+        active_skills: activeNames(state, "skill"),
+        active_agents: activeNames(state, "agent"),
+      });
+    }
+    state.task_tool_kinds = {};
+    state.task_tool_count = 0;
+    state.task_corrections = 0;
     resetFrictionCounters(state);
   } else if (event === "PreToolUse") {
     const tool = input.tool_name;
@@ -293,6 +318,9 @@ function main() {
       state.dead_end_emitted = true;
     }
 
+    state.task_tool_count += 1;
+    state.task_tool_kinds[tool] = (state.task_tool_kinds[tool] || 0) + 1;
+
     if (struggleEmittedThisTurn) {
       state.recoveryWatch = { recovered_from: struggleEmittedThisTurn, since_ts: ts, clean_count: 0, window_tools: [] };
     } else if (state.recoveryWatch) {