chore(docs): Remove canvas-tui-markdown-investigation.md

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/canvas-tui-markdown-investigation.md

@@ -1,225 +0,0 @@
-# Canvas TUI - Markdown Rendering Investigation
-
-**Status:** Open
-**Component:** `canvas-tui/src/hooks/useMarkdown.ts`
-**Date:** 2026-01-09
-
----
-
-## Problem Summary
-
-Numbered lists in the canvas TUI markdown renderer exhibit intermittent rendering failures where:
-
-1. Items are dropped (e.g., item 2 disappears)
-2. Text from adjacent items merges (e.g., "integrationsrequesting")
-3. Original markdown numbering appears instead of our renumbered output (showing "1, 3" instead of "1, 2, 3")
-
-The bug is intermittent - identical code sometimes works, sometimes fails.
-
----
-
-## Architecture
-
-```
-Content Flow:
-┌─────────────┐    ┌──────────────────┐    ┌─────────────────┐
-│ Raw Markdown│───▸│ useMarkdown hook │───▸│ Rendered ANSI   │
-└─────────────┘    └──────────────────┘    └─────────────────┘
-                           │
-                   ┌───────┴───────┐
-                   ▼               ▼
-           ┌─────────────┐  ┌─────────────┐
-           │ Numbered    │  │ cli-markdown│
-           │ Lists       │  │ (everything │
-           │ (custom)    │  │  else)      │
-           └─────────────┘  └─────────────┘
-```
-
-**Strategy:** Process content in sections. Detect numbered lists with regex, render them ourselves (to avoid cli-markdown bugs), delegate everything else to cli-markdown.
-
----
-
-## The Bug
-
-### Symptoms
-
-When the bug manifests, the output shows:
-```
-1. Platform Scalability - Addressing the infrastructure bottlenecks...
-3. Developer Experience - Improving our API...integrationsrequesting
-```
-
-Note:
-- Item 2 ("Enterprise Features") is completely missing
-- "requesting" (end of item 2's text) is merged with item 3
-- Numbers are original (1, 3) not renumbered (1, 2, 3)
-
-### What This Tells Us
-
-Our custom numbered list handler renumbers items as 1, 2, 3 based on array index:
-```typescript
-numberedListItems.map((item, i) => `  ${i + 1}. ${renderInline(item)}`)
-```
-
-If output shows original numbers (1, 3), **cli-markdown is rendering the list, not our code.**
-
-This means either:
-1. Our regex isn't detecting the numbered list items
-2. The numbered list is somehow being passed to cli-markdown
-
----
-
-## Investigation
-
-### Test 1: Regex Validation
-
-Tested the detection regex against actual file content:
-
-```javascript
-const regex = /^(\s*)(\d+)\.\s+(.+)$/;
-lines.forEach((line, i) => {
-  const match = line.match(regex);
-  console.log(`Line ${i+1}: ${match ? 'MATCH' : 'NO MATCH'}`);
-});
-```
-
-**Result:** All 3 numbered list lines MATCH correctly.
-
-### Test 2: Processing Logic in Isolation
-
-Simulated the exact processing loop outside React:
-
-```javascript
-// ... full processing logic ...
-console.log('FLUSH NUMBERED LIST, items:', numberedListItems.length);
-```
-
-**Result:** Shows "FLUSH NUMBERED LIST, items: 3" - all items captured correctly.
-
-### Test 3: Full Flow Simulation
-
-Ran the complete processing including cli-markdown calls:
-
-```
-=== AFTER POST-PROCESS ===
-  1. **Platform Scalability** - Addressing bottlenecks
-  2. **Enterprise Features** - Delivering compliance
-  3. **Developer Experience** - Improving our API
-```
-
-**Result:** Works perfectly in isolation! All 3 items, correctly renumbered.
-
-### Test 4: File Content Verification
-
-Checked actual file for encoding issues:
-```bash
-cat -A email-draft.md  # Shows $ for line endings
-xxd email-draft.md     # Shows hex bytes
-```
-
-**Result:** Clean LF line endings, no hidden characters, no blank lines between numbered items.
-
-### Test 5: Compiled Output Verification
-
-Verified the TypeScript compiled to correct JavaScript:
-```bash
-grep -A5 "flushNumberedList" dist/hooks/useMarkdown.js
-```
-
-**Result:** Compiled code matches source, includes the `\n` prefix fix.
-
----
-
-## Key Observations
-
-### The Debug String Mystery
-
-The bug behavior changed based on what string we pushed to outputSections:
-
-| Code | Behavior |
-|------|----------|
-| `outputSections.push('[DEBUG: N items]\n' + listOutput)` | **WORKS** |
-| `outputSections.push('\n' + listOutput)` | **FAILS** (intermittent) |
-| `outputSections.push(listOutput)` | **FAILS** |
-
-The only difference is the string content. Having text before the newline somehow stabilizes the behavior.
-
-### The Bullet Regex Correlation
-
-The bug appeared/worsened after adding this regex:
-```javascript
-rendered = rendered.replace(/\n\n(\s*[•\-\*]\s)/g, '\n$1');
-```
-
-This regex should NOT affect numbered lists (matches `•`, `-`, `*` but not digits). Yet removing it seems to help.
-
----
-
-## Hypotheses
-
-### H1: Section Boundary Race Condition
-
-When outputSections are joined, the string starting with `\n` might interact poorly with cli-markdown's output which may also end with newlines. The `\n{3,}` normalization could be collapsing something critical.
-
-**Evidence:** Adding text before `\n` (debug string) prevents the issue.
-
-### H2: cli-markdown State Bleeding
-
-cli-markdown might have some internal state that persists between calls, causing content from one section to affect another.
-
-**Evidence:** Processing works in isolation but fails in the app.
-
-### H3: React useMemo Timing
-
-The useMemo hook might be returning stale cached values, or the `width` dependency is causing unexpected re-renders that interact with the processing.
-
-**Evidence:** Bug is intermittent despite identical code.
-
-### H4: Regex Replacement Side Effects
-
-The bullet-stripping regex, despite not matching numbered lists, might be causing side effects through JavaScript's regex engine state (lastIndex, etc.).
-
-**Evidence:** Bug correlates with adding/removing this regex.
-
----
-
-## Current State
-
-The bullet-stripping regex has been removed. Testing needed to confirm if this resolves the numbered list issue.
-
-If confirmed, we need an alternative approach for bullet list spacing that doesn't interfere with numbered lists.
-
----
-
-## Recommended Next Steps
-
-1. **Confirm current state works** - Test with bullet regex removed
-2. **If working, isolate bullet regex issue:**
-   - Test regex in isolation
-   - Try alternative regex patterns
-   - Consider post-processing bullets separately from numbered lists
-3. **If still broken, add instrumentation:**
-   - Log outputSections array contents
-   - Log numberedListItems at flush time
-   - Compare React render vs isolated execution
-4. **Consider architectural changes:**
-   - Process all lists (bullet + numbered) with custom renderer
-   - Or use a different markdown library entirely
-
----
-
-## Code Reference
-
-**File:** `canvas-tui/src/hooks/useMarkdown.ts`
-
-Key sections:
-- Lines 57-73: Main processing loop with numbered list detection
-- Lines 45-55: `flushNumberedList()` function
-- Lines 83-84: Post-processing regex (bullet regex removed)
-
----
-
-## Related Issues
-
-- cli-markdown has known issues with numbered list rendering (drops/merges items)
-- This is why we implemented custom numbered list handling in the first place