feat(intentions): Phase 7 — if-then rules for task / time / triage triggers

Small if-then automation layer. Rules persist in SQLite; the runner
lives on the frontend and binds to the Phase 6 event bus so the rule
pipeline reuses the same delivery primitives (timer events, TTS,
Tasks navigation).

Storage:
- Migration v12 adds implementation_rules (id, enabled, trigger_kind,
  trigger_value, actions_json, last_fired_key, created_at,
  updated_at) with enabled+trigger_kind index for the runner's hot
  path.
- CRUD helpers: insert / list / get / set-enabled / mark-fired /
  delete, plus a round-trip test.

Commands (all main-window-guarded via ensure_main_window):
- list_implementation_rules
- create_implementation_rule — validates HH:MM, checks the target
  task exists at save time for surface-task actions, caps
  speak-line at 240 chars, pins v1 timers to 5 minutes.
- set_implementation_rule_enabled
- mark_implementation_rule_fired — main-thread idempotency shim so
  the runner can atomically claim a fire.
- delete_implementation_rule

Runner (implementationIntentions.svelte.ts):
- Subscribes to kon:task-completed and kon:morning-triage-finished
  (MorningTriageModal now emits on all three exit paths — empty,
  skipped, picked — so skip counts as finishing).
- 30 s poll for time-of-day rules, plus an immediate check on startup
  so a rule whose time has already passed today catches up once.
- Idempotency via last_fired_key composed as YYYY-MM-DD@HH:MM for
  time rules; new time rules whose HH:MM has already passed today
  are pre-seeded so they don't fire retroactively on save.
- Rules are paused when Nudges "Mute for now" is on — a hard mute
  stops all rule delivery in addition to OS notifications.
- Stale-task safety: if a surface-task action's target has been
  deleted, the runner opens Tasks and warns clearly rather than
  pretending to surface something that's gone.

Editor (ImplementationRulesEditor.svelte):
- Lives in Settings under a new "If-then rules" accordion section.
- `If` picker: time of day (with time input), a task completes,
  morning triage finishes.
- `Then` composer: optional surface (inbox / today / all tasks /
  specific task), optional 5-min timer, optional speak-aloud line.
- Saved rules list with enable toggle + delete.

Rules table integration for Phase 10b rename sweep: add
implementation_rules to the kon.db → corbie.db migration shim when
that phase lands.

Gates: fmt, clippy -D warnings, cargo test 265/0, svelte-check
0/0, npm build green. Pre-existing Vite chunk warning on sounds.ts
is unrelated to Phase 7.

src/lib/stores/implementationIntentions.svelte.ts

@@ -0,0 +1,260 @@
+// Phase 7 implementation intentions. Rules are persisted in SQLite via
+// Tauri commands; this frontend runner binds them to the Phase 6 event
+// bus and executes their small local actions.
+
+import { invoke } from "@tauri-apps/api/core";
+import type {
+  ImplementationRule,
+  ImplementationRuleAction,
+  ImplementationRuleDraft,
+} from "$lib/types/app";
+import { hasTauriRuntime } from "$lib/utils/runtime.js";
+import { page, settings, tasks } from "$lib/stores/page.svelte.js";
+import { toasts } from "$lib/stores/toasts.svelte.js";
+
+const TIME_RULE_POLL_MS = 30_000;
+const RULES_CHANGED_EVENT = "kon:implementation-rules-changed";
+
+export const implementationRules = $state<ImplementationRule[]>([]);
+
+let loaded = false;
+let started = false;
+let timePollHandle: ReturnType<typeof setInterval> | null = null;
+const firingRules = new Set<string>();
+
+function todayLocalKey(): string {
+  const d = new Date();
+  return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, "0")}-${String(d.getDate()).padStart(2, "0")}`;
+}
+
+function currentHHMM(): string {
+  const d = new Date();
+  return `${String(d.getHours()).padStart(2, "0")}:${String(d.getMinutes()).padStart(2, "0")}`;
+}
+
+function hasTimeAlreadyPassed(hhmm: string): boolean {
+  return currentHHMM() >= hhmm;
+}
+
+export function initialLastFiredKeyForTimeRule(hhmm: string): string | null {
+  return hasTimeAlreadyPassed(hhmm) ? `${todayLocalKey()}@${hhmm}` : null;
+}
+
+function replaceRule(next: ImplementationRule): void {
+  const idx = implementationRules.findIndex((rule) => rule.id === next.id);
+  if (idx >= 0) implementationRules[idx] = next;
+  else implementationRules.unshift(next);
+}
+
+function broadcastRulesChanged(): void {
+  if (typeof window === "undefined") return;
+  window.dispatchEvent(new CustomEvent(RULES_CHANGED_EVENT));
+}
+
+export async function loadImplementationRules(force = false): Promise<void> {
+  if (!hasTauriRuntime()) {
+    implementationRules.length = 0;
+    loaded = true;
+    return;
+  }
+  if (loaded && !force) return;
+  const rows = await invoke<ImplementationRule[]>("list_implementation_rules");
+  implementationRules.splice(0, implementationRules.length, ...rows);
+  loaded = true;
+}
+
+export async function createImplementationRule(
+  draft: ImplementationRuleDraft,
+): Promise<ImplementationRule> {
+  const row = await invoke<ImplementationRule>("create_implementation_rule", { request: draft });
+  replaceRule(row);
+  broadcastRulesChanged();
+  return row;
+}
+
+export async function setImplementationRuleEnabled(id: string, enabled: boolean): Promise<void> {
+  const row = await invoke<ImplementationRule>("set_implementation_rule_enabled", { id, enabled });
+  replaceRule(row);
+  broadcastRulesChanged();
+}
+
+export async function deleteImplementationRule(id: string): Promise<void> {
+  await invoke("delete_implementation_rule", { id });
+  const idx = implementationRules.findIndex((rule) => rule.id === id);
+  if (idx >= 0) implementationRules.splice(idx, 1);
+  broadcastRulesChanged();
+}
+
+async function markRuleFired(rule: ImplementationRule, firedKey: string): Promise<void> {
+  const row = await invoke<ImplementationRule>("mark_implementation_rule_fired", {
+    id: rule.id,
+    firedKey,
+  });
+  replaceRule(row);
+}
+
+function actionLabel(action: ImplementationRuleAction): string {
+  if (action.kind === "speak_line") return `Speak "${action.text}"`;
+  if (action.kind === "start_timer") return "Start a 5-minute timer";
+  if (action.kind === "surface") {
+    if (action.target === "task") return `Surface ${action.label || "task"}`;
+    if (action.target === "inbox") return "Surface inbox";
+    if (action.target === "today") return "Surface today";
+    return "Surface tasks";
+  }
+  return "Action";
+}
+
+export function ruleSummary(rule: ImplementationRule): string {
+  const when = rule.triggerKind === "time_of_day"
+    ? `At ${rule.triggerValue}`
+    : rule.triggerKind === "task_completed"
+      ? "After a task completes"
+      : "After morning triage";
+  return `${when} -> ${rule.actions.map(actionLabel).join(" + ")}`;
+}
+
+function surfaceAction(action: Extract<ImplementationRuleAction, { kind: "surface" }>): void {
+  if (action.target === "task" && action.taskId) {
+    const task = tasks.find((candidate) => candidate.id === action.taskId);
+    if (!task) {
+      // The rule outlived its target. Don't fake a success toast —
+      // surface the full list so the user can still act, and tell
+      // them why the specific task isn't there. Cached label used
+      // only for identification, not as a claim of surfacing.
+      page.current = "tasks";
+      page.taskSidebarOpen = true;
+      const cachedLabel = action.label?.trim();
+      toasts.warn(
+        "Rule target missing",
+        cachedLabel
+          ? `The task "${cachedLabel}" is gone — edit the rule to point at something else.`
+          : "That rule's task is gone — edit the rule to point at something else.",
+      );
+      return;
+    }
+    page.current = "tasks";
+    page.taskSidebarOpen = true;
+    toasts.info("Task ready", task.text);
+    return;
+  }
+
+  page.current = "tasks";
+  page.taskSidebarOpen = true;
+
+  if (action.target === "inbox") {
+    toasts.info("Inbox is here", "Your task list is open.");
+  } else if (action.target === "today") {
+    toasts.info("Today's list is here", "Your task list is open.");
+  } else {
+    toasts.info("Tasks are here", "Your list is open.");
+  }
+}
+
+async function executeAction(action: ImplementationRuleAction): Promise<void> {
+  if (action.kind === "surface") {
+    surfaceAction(action);
+    return;
+  }
+  if (action.kind === "start_timer") {
+    window.dispatchEvent(new CustomEvent("kon:start-timer", {
+      detail: {
+        taskId: action.taskId ?? null,
+        seconds: 300,
+        label: action.label ?? "5-minute timer",
+      },
+    }));
+    return;
+  }
+  if (action.kind === "speak_line") {
+    await invoke("tts_speak", {
+      text: action.text,
+      rate: settings.ttsRate,
+      voice: settings.ttsVoice ?? null,
+    });
+  }
+}
+
+async function fireRule(rule: ImplementationRule, firedKey?: string): Promise<void> {
+  if (!rule.enabled) return;
+  if (settings.nudgesMuted) return;
+  if (firedKey && rule.lastFiredKey === firedKey) return;
+  if (firingRules.has(rule.id)) return;
+
+  firingRules.add(rule.id);
+  try {
+    for (const action of rule.actions) {
+      try {
+        await executeAction(action);
+      } catch {
+        // Rule actions are assistance, not critical workflow. Keep going
+        // so a missing TTS voice does not block surfacing a task.
+      }
+    }
+    if (firedKey) {
+      await markRuleFired(rule, firedKey);
+    }
+  } finally {
+    firingRules.delete(rule.id);
+  }
+}
+
+function timeRuleFiredKey(rule: ImplementationRule): string {
+  return `${todayLocalKey()}@${rule.triggerValue}`;
+}
+
+async function checkTimeRules(): Promise<void> {
+  if (!loaded) await loadImplementationRules();
+  for (const rule of implementationRules) {
+    if (rule.triggerKind !== "time_of_day") continue;
+    if (!rule.enabled) continue;
+    if (currentHHMM() < rule.triggerValue) continue;
+    const firedKey = timeRuleFiredKey(rule);
+    if (rule.lastFiredKey === firedKey) continue;
+    await fireRule(rule, firedKey);
+  }
+}
+
+function onTaskCompleted(): void {
+  for (const rule of implementationRules) {
+    if (rule.triggerKind === "task_completed") void fireRule(rule);
+  }
+}
+
+function onMorningTriageFinished(): void {
+  for (const rule of implementationRules) {
+    if (rule.triggerKind === "morning_triage_finished") void fireRule(rule);
+  }
+}
+
+function onRulesChanged(): void {
+  void checkTimeRules();
+}
+
+export function startImplementationIntentions(): void {
+  if (started) return;
+  if (typeof window === "undefined") return;
+  started = true;
+
+  void loadImplementationRules(true)
+    .then(() => checkTimeRules())
+    .catch(() => {});
+  window.addEventListener("kon:task-completed", onTaskCompleted);
+  window.addEventListener("kon:morning-triage-finished", onMorningTriageFinished);
+  window.addEventListener(RULES_CHANGED_EVENT, onRulesChanged);
+  timePollHandle = setInterval(() => {
+    void checkTimeRules().catch(() => {});
+  }, TIME_RULE_POLL_MS);
+}
+
+export function stopImplementationIntentions(): void {
+  if (!started) return;
+  started = false;
+  window.removeEventListener("kon:task-completed", onTaskCompleted);
+  window.removeEventListener("kon:morning-triage-finished", onMorningTriageFinished);
+  window.removeEventListener(RULES_CHANGED_EVENT, onRulesChanged);
+  if (timePollHandle !== null) {
+    clearInterval(timePollHandle);
+    timePollHandle = null;
+  }
+}