refactor: Complete library renaming from qdata to ml4t-data

Major refactoring to align library naming with sibling libraries (ml4t-features,
ml4t-eval, ml4t-backtest) and add corporate actions educational materials.

**Library Renaming (qdata → ml4t-data)**:
- Package name: `ml4t-data` (for pip install)
- Python imports: `ml4t.data` (for code)
- Class names: `QDataConfig` → `DataConfig`
- Updated 1,100+ references across all files
- Deleted: `docs/extending_qdata.md`
- Added: `docs/extending_ml4t_data.md`

**Corporate Actions Module**:
- Location: `src/ml4t/data/adjustments/core.py`
- Industry-standard backward adjustment formula
- Adaptive reverse split detection algorithm
- 70% validation success rate on 100 random stocks
- Comprehensive investigation documented in:
  - `CORPORATE_ACTIONS_FINAL_REPORT.md`
  - `YAHOO_QUANDL_FEASIBILITY.md`
  - `CORPORATE_ACTIONS_FINDINGS.md`

**Educational Demo Project**:
- Location: `~/ml3t/data/equities/corporate_actions_demo/`
- Purpose: ML4T book chapter on data quality challenges
- Demonstrates real-world issues with free data sources
- Includes Python script and Jupytext notebook format
- Documents Yahoo Finance vs Quandl incompatibilities

**Code Quality Improvements**:
- Fixed all pre-commit hook violations (27 errors)
- F821: Added TYPE_CHECKING import for DataObject in hive.py
- E712: Replaced boolean == True/False with idiomatic checks
- F841: Removed unused variables in example scripts
- F401: Fixed aiofiles import using importlib.util.find_spec
- B007: Renamed unused loop variables with _ prefix
- SIM108: Simplified if-else to ternary operators
- Auto-formatted 28 files with ruff

**Test Results**:
- ✅ 849 tests passed
- ⏭️ 23 skipped (flaky Yahoo tests in parallel execution)
- ⏱️ Total time: 29 minutes 12 seconds
- 🎯 Exit code: 0

**Documentation**:
- Added comprehensive validation reports
- Educational README for corporate actions demo
- Extensive feasibility analysis of Yahoo/Quandl integration
- Project summary and completion status

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: stefan-jansen

.claude/analysis/CRITICAL_TEST_FIXES.md

@@ -13,7 +13,7 @@
 Method doesn't handle lowercase or mixed-case symbols correctly. Causes ~20-30 test failures.
 
 ### File
-`/home/stefan/ml4t/software/data/src/qdata/providers/coingecko.py`
+`/home/stefan/ml4t/software/data/src/ml4t.data/providers/coingecko.py`
 
 ### Current Code (Lines 376-394)
 ```python
@@ -118,7 +118,7 @@ oanda = [
     "oandapyV20>=0.7.0",
 ]
 all-providers = [
-    "qdata[yahoo,databento,oanda]",
+    "ml4t.data[yahoo,databento,oanda]",
 ]
 
 # Development dependencies
@@ -148,7 +148,7 @@ api = [
 ]
 
 all-providers = [
-    "qdata[yahoo,databento,oanda]",
+    "ml4t.data[yahoo,databento,oanda]",
 ]
 
 # Development dependencies
@@ -161,7 +161,7 @@ dev = [
 
 # All optional dependencies
 all = [
-    "qdata[all-providers,dev,docs,api]",  # ← Update to include 'api'
+    "ml4t.data[all-providers,dev,docs,api]",  # ← Update to include 'api'
 ]
 ```
 
@@ -197,7 +197,7 @@ python_functions = ["test_*"]
 addopts = [
     "-ra",
     "--strict-markers",
-    "--cov=qdata",
+    "--cov=ml4t.data",
     "--cov-report=term-missing",
     "--cov-report=html",
 ]
@@ -258,7 +258,7 @@ pytest -m ""
 pytest -m "integration"
 
 # Run with coverage (unit tests only)
-pytest --cov=qdata --cov-report=html
+pytest --cov=ml4t.data --cov-report=html
 ```
 
 ---
@@ -408,7 +408,7 @@ pytest -x
 pytest -s
 
 # Generate coverage report
-pytest --cov=qdata --cov-report=html
+pytest --cov=ml4t.data --cov-report=html
 open htmlcov/index.html
 ```
 
@@ -489,7 +489,7 @@ pytest tests/test_api/test_main.py
 
 | File | Change | Impact |
 |------|--------|--------|
-| `src/qdata/providers/coingecko.py` | Fix symbol_to_id method | 20-30 tests fixed |
+| `src/ml4t.data/providers/coingecko.py` | Fix symbol_to_id method | 20-30 tests fixed |
 | `pyproject.toml` | Add `api` optional deps | API tests can run |
 | `pyproject.toml` | Update pytest config | Default runs fast |
 | `tests/test_yahoo_provider.py` | Add integration marker | Skipped by default |

.claude/analysis/TEST_AUDIT_EXECUTIVE_SUMMARY.md

@@ -1,4 +1,4 @@
-# QData Test Suite - Executive Summary
+# ML4T Data Test Suite - Executive Summary
 
 **Date**: 2025-11-14
 **Current Status**: 149 failed, 662 passed, 190 skipped, 6 errors
@@ -95,7 +95,7 @@ api = ["slowapi>=0.1.8"]
 ## The Fix (30 minutes)
 
 ### Step 1: Fix CoinGecko Bug (5 minutes) 🔴
-**File**: `src/qdata/providers/coingecko.py:376`
+**File**: `src/ml4t.data/providers/coingecko.py:376`
 **Action**: Replace `symbol_to_id()` method with case-insensitive version
 **Result**: 20-30 tests fixed
 
@@ -167,7 +167,7 @@ pytest -m ""  # Run everything
 
 | File | Lines Changed | Type |
 |------|---------------|------|
-| `src/qdata/providers/coingecko.py` | ~20 | Bug fix |
+| `src/ml4t.data/providers/coingecko.py` | ~20 | Bug fix |
 | `pyproject.toml` | ~10 | Config |
 | `tests/test_yahoo_provider.py` | 2 | Marker |
 | `tests/test_binance.py` | 2 | Marker |

.claude/analysis/TEST_FIX_CHECKLIST.md

@@ -8,7 +8,7 @@
 ## ✅ Critical Fixes (Do First - 15 minutes)
 
 ### [ ] Fix 1: CoinGecko symbol_to_id Bug (5 min)
-**File**: `src/qdata/providers/coingecko.py`
+**File**: `src/ml4t.data/providers/coingecko.py`
 **Line**: 376
 **Action**: Replace entire `symbol_to_id` method
 
@@ -55,7 +55,7 @@ api = [
 **And update** `all` section:
 ```toml
 all = [
-    "qdata[all-providers,dev,docs,api]",  # ← Add 'api'
+    "ml4t.data[all-providers,dev,docs,api]",  # ← Add 'api'
 ]
 ```
 
@@ -176,14 +176,14 @@ pytest -m integration
 pytest tests/integration/test_coingecko.py
 
 # With coverage
-pytest --cov=qdata --cov-report=html
+pytest --cov=ml4t.data --cov-report=html
 ```
 
 ---
 
 ## 📁 Files to Change
 
-- [ ] `src/qdata/providers/coingecko.py` (bug fix)
+- [ ] `src/ml4t.data/providers/coingecko.py` (bug fix)
 - [ ] `pyproject.toml` (config + dependencies)
 - [ ] `tests/test_yahoo_provider.py` (marker)
 - [ ] `tests/test_binance.py` (marker)
@@ -220,7 +220,7 @@ pytest --help | grep "\-m"
 ### "CoinGecko tests still failing"
 Verify method was replaced:
 ```bash
-grep -A 10 "def symbol_to_id" src/qdata/providers/coingecko.py
+grep -A 10 "def symbol_to_id" src/ml4t.data/providers/coingecko.py
 # Should see: symbol_upper = symbol.upper()
 ```
 

.claude/analysis/TEST_SUITE_COMPREHENSIVE_AUDIT.md

@@ -1,4 +1,4 @@
-# QData Test Suite - Comprehensive Audit & Fix Plan
+# ML4T Data Test Suite - Comprehensive Audit & Fix Plan
 
 **Date**: 2025-11-14
 **Auditor**: Test Engineer Agent
@@ -9,7 +9,7 @@
 
 ## Executive Summary
 
-The qdata test suite is in **poor condition** requiring immediate systematic cleanup:
+The ml4t.data test suite is in **poor condition** requiring immediate systematic cleanup:
 
 - **Primary Issues**: Missing dependencies (slowapi, optional providers), excessive integration test runtime, known bugs in provider code
 - **Collection Errors**: 6 errors blocking test discovery (already partially fixed via skip markers)
@@ -104,7 +104,7 @@ Based on code analysis, failures fall into these categories:
 
 #### A1. CoinGecko `symbol_to_id()` Bug (HIGH PRIORITY)
 
-**File**: `src/qdata/providers/coingecko.py:376`
+**File**: `src/ml4t.data/providers/coingecko.py:376`
 **Bug**: Method doesn't handle lowercase/mixed-case symbols correctly
 
 **Current Implementation**:
@@ -243,7 +243,7 @@ api = [
     "slowapi>=0.1.8",  # ❌ MISSING - ADD THIS
 ]
 all-providers = [
-    "qdata[yahoo,databento,oanda,api]",
+    "ml4t.data[yahoo,databento,oanda,api]",
 ]
 ```
 
@@ -269,7 +269,7 @@ all-providers = [
 
 ### Fix #1: CoinGecko symbol_to_id Bug (CRITICAL)
 
-**File**: `/home/stefan/ml4t/software/data/src/qdata/providers/coingecko.py`
+**File**: `/home/stefan/ml4t/software/data/src/ml4t.data/providers/coingecko.py`
 **Line**: 376-394
 
 **Current Code**:
@@ -343,7 +343,7 @@ api = [
 
 # Update all-providers
 all = [
-    "qdata[all-providers,dev,docs,api]",
+    "ml4t.data[all-providers,dev,docs,api]",
 ]
 ```
 
@@ -537,7 +537,7 @@ pip install -e ".[all]"
 pytest --maxfail=0 --tb=short
 
 # Generate coverage report
-pytest --cov=qdata --cov-report=html --cov-report=term
+pytest --cov=ml4t.data --cov-report=html --cov-report=term
 ```
 
 ---
@@ -547,7 +547,7 @@ pytest --cov=qdata --cov-report=html --cov-report=term
 ### 🔴 CRITICAL (Do First - 30 minutes)
 
 1. **Fix CoinGecko symbol_to_id bug**
-   - File: `src/qdata/providers/coingecko.py:376`
+   - File: `src/ml4t.data/providers/coingecko.py:376`
    - Replace method with fixed version (see Fix #1)
    - Run: `pytest tests/integration/test_coingecko.py::TestCoinGeckoProvider::test_symbol_to_id_mapping -v`
    - Expected: 3-4 tests now passing
@@ -605,7 +605,7 @@ pytest --cov=qdata --cov-report=html --cov-report=term
     - Update: Import paths if needed
 
 11. **Add test coverage reporting**
-    - Run: `pytest --cov=qdata --cov-report=html`
+    - Run: `pytest --cov=ml4t.data --cov-report=html`
     - Identify: Untested code paths
     - Add: Unit tests for uncovered critical code
 
@@ -688,7 +688,7 @@ pytest --cov=qdata --cov-report=html --cov-report=term
 ## Part 12: Files Requiring Changes
 
 ### Code Fixes
-- ✅ `src/qdata/providers/coingecko.py` - Fix symbol_to_id method
+- ✅ `src/ml4t.data/providers/coingecko.py` - Fix symbol_to_id method
 
 ### Configuration Files
 - ✅ `pyproject.toml` - Add slowapi, update pytest config
@@ -706,7 +706,7 @@ pytest --cov=qdata --cov-report=html --cov-report=term
 
 ## Conclusion
 
-The qdata test suite requires **systematic cleanup**, not ad-hoc fixes. The primary issues are:
+The ml4t.data test suite requires **systematic cleanup**, not ad-hoc fixes. The primary issues are:
 
 1. **Critical Bug**: CoinGecko symbol_to_id doesn't handle case-insensitive symbols
 2. **Poor Organization**: Unit and integration tests mixed together