feat(web): define ChatEvent discriminated union, eliminate all any sites (R9)

Created web/src/lib/types.ts with discriminated unions for SSE event
payloads: ChatEvent (7 variants: session, tool_use, tool_result,
text_delta, text, done, error), ToolCallResult, MessageContent, and
typed data shapes for live events (PlanProposedData, PlanStepEventData,
QuestionRaisedData, QuestionAnsweredData, EntityTouchedData,
HealthChangedData) plus WailsGlobal for the desktop bridge.

Replaced all ~15 `any` sites across 7 files:
- api.ts: Message.content any -> MessageContent | string; removed local
  ChatEvent interface (now imported from types.ts as a discriminated
  union); JSON.parse cast to ChatEvent.
- stores/chat.ts: removed local ToolCallResult interface (imported from
  types.ts, re-exported for backward compat); extractApprovals accesses
  args with typeof guards instead of implicit any access; toChatMessages
  handles string|object Message.content cleanly.
- stores/activity.ts: update_plan_step seq/status extracted via typeof
  guards instead of `as any` casts; toolActivityLabel uses a str() helper
  for safe string extraction from unknown args.
- stores/workspace.ts: applyPlanStepEvent takes PlanStepEventData;
  applyEvent casts data to Record<string, unknown>; switch cases cast to
  typed interfaces (PlanProposedData, QuestionRaisedData, etc.) instead
  of `as any`; applyHealthChanged uses HealthChangedData.
- Config.svelte: (window as any).wails -> typed WailsGlobal cast;
  catch (e: any) -> catch (e: unknown) with instanceof Error check.
- utils.ts: WithoutChild/WithoutChildren `any` -> `unknown`.
- vite.config.ts: authProxy proxy/proxyReq `any` -> ProxyOptions type.

Result: eslint no-explicit-any warnings dropped 12 -> 0. Tests (6/6) and
build pass. VERSION 0.7.10 -> 0.7.11. Plan R9 marked done.

web/src/lib/stores/workspace.ts

@@ -2,6 +2,14 @@ import { writable, derived, get } from 'svelte/store'
 import { liveEvents, subscribeEvents } from './events'
 import { currentSession, sessions, loadSessions } from './chat'
 import { fetchPlan, fetchQuestions, type PlanStep, type SessionQuestion } from '$lib/api'
+import type {
+  PlanProposedData,
+  PlanStepEventData,
+  QuestionRaisedData,
+  QuestionAnsweredData,
+  EntityTouchedData,
+  HealthChangedData
+} from '$lib/types'
 
 // workspace.ts is the live "what is this task doing right now" surface for the
 // TaskContextPanel: plan progress, the pinned operator question, and entities
@@ -65,9 +73,9 @@ async function hydrate(sessionId: string) {
   questions.set(qs)
 }
 
-function applyPlanStepEvent(sessionId: string, type: string, data: any) {
-  const stepID = data?.step_id as string | undefined
-  const seq = data?.seq as number | undefined
+function applyPlanStepEvent(sessionId: string, type: string, data: PlanStepEventData) {
+  const stepID = data?.step_id
+  const seq = data?.seq
   planSteps.update((steps) => {
     const i = steps.findIndex((s) => (stepID && s.id === stepID) || (seq != null && s.seq === seq))
     if (i === -1) return steps
@@ -80,7 +88,7 @@ function applyPlanStepEvent(sessionId: string, type: string, data: any) {
 function applyEvent(ev: { type: string; correlation_id?: string | null; data?: unknown }) {
   const sid = get(currentSession)
   if (!sid || ev.correlation_id !== sid) return
-  const data = (ev.data ?? {}) as any
+  const data = (ev.data ?? {}) as Record<string, unknown>
 
   // Task fields (status/goal/outcome) live on the session row — refetch the
   // (cheap) session list so the UI picks up the change without a
@@ -99,46 +107,49 @@ function applyEvent(ev: { type: string; correlation_id?: string | null; data?: u
   }
 
   switch (ev.type) {
-    case 'plan.proposed':
-      if (Array.isArray(data.steps)) {
-        const incoming = data.steps.map((s: any) => ({
+    case 'plan.proposed': {
+      const d = data as unknown as PlanProposedData
+      if (Array.isArray(d.steps)) {
+        const incoming = d.steps.map((s) => ({
           id: s.id, seq: s.seq, title: s.title, detail: s.detail ?? '',
           status: 'pending' as const, target_slug: s.target_slug || undefined
         }))
-        // The server appends rather than replaces once any step has started
-        // (see store.go proposePlan) — mirror that here so a model that calls
-        // propose_plan once per step still shows the FULL running history in
-        // the panel, not just its latest call's single step.
-        planSteps.update((existing) => (data.appended ? [...existing, ...incoming] : incoming))
+        planSteps.update((existing) => (d.appended ? [...existing, ...incoming] : incoming))
       }
       break
+    }
     case 'plan.step.started':
     case 'plan.step.finished':
-      applyPlanStepEvent(sid, ev.type, data)
+      applyPlanStepEvent(sid, ev.type, data as unknown as PlanStepEventData)
       break
-    case 'question.raised':
+    case 'question.raised': {
+      const d = data as unknown as QuestionRaisedData
       questions.update((qs) => [
         {
-          id: data.question_id, prompt: data.prompt ?? '',
-          context: { why: data.why, options: data.options, entities: data.entities },
+          id: d.question_id, prompt: d.prompt ?? '',
+          context: { why: d.why, options: d.options, entities: d.entities },
           status: 'open', created_at: new Date().toISOString()
         },
-        ...qs.filter((q) => q.id !== data.question_id)
+        ...qs.filter((q) => q.id !== d.question_id)
       ])
       break
-    case 'question.answered':
+    }
+    case 'question.answered': {
+      const d = data as unknown as QuestionAnsweredData
       questions.update((qs) =>
-        qs.map((q) => (q.id === data.question_id ? { ...q, status: 'answered', answer: data.answer } : q))
+        qs.map((q) => (q.id === d.question_id ? { ...q, status: 'answered', answer: d.answer } : q))
       )
       break
-    case 'entity.touched':
-      if (data.slug) {
+    }
+    case 'entity.touched': {
+      const d = data as unknown as EntityTouchedData
+      if (d.slug) {
         const now = Date.now()
-        touched.update((t) => [{ slug: data.slug, tool: data.tool ?? '', ts: now }, ...t].slice(0, TOUCHED_MAX))
+        touched.update((t) => [{ slug: d.slug, tool: d.tool ?? '', ts: now }, ...t].slice(0, TOUCHED_MAX))
       }
       break
+    }
     case 'knowledge.recorded':
-      // No dedicated store — knowledge cards refetch on completion signal.
       break
   }
 }
@@ -148,11 +159,11 @@ function applyEvent(ev: { type: string; correlation_id?: string | null; data?: u
 // by correlation_id (health events don't carry one).
 function applyHealthChanged(ev: { type: string; data?: unknown }) {
   if (ev.type !== 'health.changed') return
-  const data = (ev.data ?? {}) as any
+  const data = (ev.data ?? {}) as HealthChangedData
   if (!data.slug) return
   const isRelevant = get(touched).some((t) => t.slug === data.slug)
   if (!isRelevant) return
-  healthDiffs.update((d) => [{ slug: data.slug, from: data.from, to: data.to, ts: Date.now() }, ...d].slice(0, 8))
+  healthDiffs.update((d) => [{ slug: data.slug, from: data.from ?? '', to: data.to ?? '', ts: Date.now() }, ...d].slice(0, 8))
 }
 
 // startWorkspace opens the global event subscription and begins tracking the