Tighten conversation rhythm, flatten the tool list, and smooth streaming text

Conversation rhythm:
- Single `--paragraph-gap` knob drives paragraph spacing both inside a
  markdown block and between consecutive prose parts, out-specifying Tailwind
  Typography's prose margins. Code cards carry the same gap themselves so it
  holds at any Streamdown nesting depth.
- Two-tier vertical rhythm: `--turn-block-gap` separates scaffolding (tools /
  thinking) from the reply; `--tool-row-gap` keeps a tool run tight.
- Drop the prose indent so prose, tools, todos, and thinking share one left
  edge. `---` renders as quiet spacing, not a heavy rule.

Flat tool list:
- Tools always render as a standalone-row stack, never a "Tool actions · N
  steps" group. assistant-ui slices the tool range unstably (interleaved live
  vs. reconstructed-consecutive when settled), so grouping reshuffled the whole
  turn the instant it settled. Flat rows are pixel-identical either way.
- Inline approvals can no longer be buried in a collapsed group body.
- Remove the now-dead grouping helpers from tool-fallback-model.

Empty thinking:
- Suppress reasoning disclosures with no visible text (encrypted / spinner-
  coerced reasoning) instead of leaving an empty "Thinking" header.
- Tail stall indicator returns "thinking" when a running turn goes quiet.

Streaming cadence:
- Smooth character-reveal decouples visible cadence from bursty arrival.
- Flush queued text deltas before applying tool events so a tool row can't
  jump ahead of its preceding text.
- Disable Nagle on the GUI WebSocket so per-token frames aren't coalesced.

Polish: clarify/patch/vision_analyze tool meta, queue-panel + diff-lines
spacing, sticky human bubble expands on focus (not hover).

apps/desktop/src/components/assistant-ui/tool-fallback-model.ts

@@ -88,10 +88,12 @@ const TOOL_META: Record<string, ToolMeta> = {
     tone: 'browser'
   },
   browser_type: { done: 'Typed on page', pending: 'Typing on page', icon: 'globe', tone: 'browser' },
+  clarify: { done: 'Asked a question', pending: 'Asking a question', icon: 'question', tone: 'agent' },
   edit_file: { done: 'Edited file', pending: 'Editing file', icon: 'edit', tone: 'file' },
   execute_code: { done: 'Ran code', pending: 'Running code', icon: 'terminal', tone: 'terminal' },
   image_generate: { done: 'Generated image', pending: 'Generating image', icon: 'file-media', tone: 'image' },
   list_files: { done: 'Listed files', pending: 'Listing files', icon: 'files', tone: 'file' },
+  patch: { done: 'Patched file', pending: 'Patching file', icon: 'diff', tone: 'file' },
   read_file: { done: 'Read file', pending: 'Reading file', icon: 'file', tone: 'file' },
   search_files: { done: 'Searched files', pending: 'Searching files', icon: 'search', tone: 'file' },
   session_search_recall: {
@@ -102,6 +104,7 @@ const TOOL_META: Record<string, ToolMeta> = {
   },
   terminal: { done: 'Ran command', pending: 'Running command', icon: 'terminal', tone: 'terminal' },
   todo: { done: 'Updated todos', pending: 'Updating todos', icon: 'tools', tone: 'agent' },
+  vision_analyze: { done: 'Analyzed image', pending: 'Analyzing image', icon: 'eye', tone: 'image' },
   web_extract: { done: 'Read webpage', pending: 'Reading webpage', icon: 'globe', tone: 'web' },
   web_search: { done: 'Searched web', pending: 'Searching web', icon: 'search', tone: 'web' },
   write_file: { done: 'Edited file', pending: 'Editing file', icon: 'edit', tone: 'file' }
@@ -1268,124 +1271,3 @@ export function buildToolView(part: ToolPart, inlineDiff: string): ToolView {
     tone: meta.tone
   }
 }
-
-function isToolPart(part: unknown): part is ToolPart {
-  if (!part || typeof part !== 'object') {
-    return false
-  }
-
-  const row = part as Record<string, unknown>
-
-  return row.type === 'tool-call' && typeof row.toolName === 'string'
-}
-
-export function groupToolParts(content: unknown): ToolPart[][] {
-  if (!Array.isArray(content)) {
-    return []
-  }
-
-  const groups: ToolPart[][] = []
-  let current: ToolPart[] = []
-
-  for (const part of content) {
-    // todo parts render in their own hoisted panel; skip from grouped tools.
-    if (isToolPart(part) && part.toolName !== 'todo') {
-      current.push(part)
-
-      continue
-    }
-
-    if (current.length) {
-      groups.push(current)
-      current = []
-    }
-  }
-
-  if (current.length) {
-    groups.push(current)
-  }
-
-  return groups
-}
-
-export function groupStatus(parts: ToolPart[]): ToolStatus {
-  if (parts.some(p => p.result === undefined)) {
-    return 'running'
-  }
-
-  const statuses = parts.map(part => toolStatus(part, parseMaybeObject(part.result)))
-  const hasError = statuses.includes('error')
-
-  if (!hasError) {
-    return 'success'
-  }
-
-  return statuses.at(-1) === 'success' ? 'warning' : 'error'
-}
-
-export function groupTitle(parts: ToolPart[]): string {
-  const prefix = PREFIX_META.find(p => parts.every(part => part.toolName.startsWith(p.prefix)))
-  const verb = prefix?.verb || 'Tool'
-
-  return `${verb} actions · ${parts.length} steps`
-}
-
-export function groupPreviewTargets(parts: ToolPart[]): string[] {
-  const seen = new Set<string>()
-  const targets: string[] = []
-
-  for (const part of parts) {
-    const view = buildToolView(part, inlineDiffFromResult(part.result))
-    const target = view.previewTarget
-
-    if (target && isPreviewableTarget(target) && !seen.has(target)) {
-      seen.add(target)
-      targets.push(target)
-    }
-  }
-
-  return targets
-}
-
-export function groupFailedStepCount(parts: ToolPart[]): number {
-  return parts.filter(part => toolStatus(part, parseMaybeObject(part.result)) === 'error').length
-}
-
-export function groupTotalDurationLabel(parts: ToolPart[]): string {
-  const seconds = parts.reduce((sum, part) => {
-    const value = numberValue(parseMaybeObject(part.result).duration_s)
-
-    return sum + (value && value > 0 ? value : 0)
-  }, 0)
-
-  if (!seconds) {
-    return ''
-  }
-
-  return formatDurationSeconds(seconds)
-}
-
-export function groupTailSubtitle(parts: ToolPart[]): string {
-  const tail = parts.at(-1)
-
-  return tail ? buildToolView(tail, '').subtitle : ''
-}
-
-export function groupCopyText(parts: ToolPart[]): string {
-  return parts
-    .map(part => {
-      const view = buildToolView(part, '')
-      const lines = [view.title]
-
-      if (view.subtitle && view.subtitle !== view.title) {
-        lines.push(view.subtitle)
-      }
-
-      if (view.detail && view.detail !== view.subtitle) {
-        lines.push(view.detail)
-      }
-
-      return lines.join('\n')
-    })
-    .join('\n\n')
-}