Implement assignment matching engine with issue reporting

.github/copilot-tasks.md

@@ -45,11 +45,11 @@ Projekt vollstaendig umsetzen: aus PS_PW.xlsx und Stellenbeschreibungen.xlsx mon
 - [x] T7: Foerderquote berechnen
 	- [x] Formel: funded_weekly_hours / contract_weekly_hours * 100
 	- [x] Rundungs-/Vergleichsregeln definieren
-- [ ] T8: Matching-Engine bauen
-	- [ ] Primaerschluessel Name anwenden
-	- [ ] Kandidaten via Stellenanteil/Foerderquote aufloesen
-	- [ ] Ambigue und fehlende Treffer sauber markieren
-	- [ ] Hinweise aus Bemerkungsspalte als Validierungshinweis weitergeben
+- [x] T8: Matching-Engine bauen
+	- [x] Primaerschluessel Name anwenden
+	- [x] Kandidaten via Stellenanteil/Foerderquote aufloesen
+	- [x] Ambigue und fehlende Treffer sauber markieren
+	- [x] Hinweise aus Bemerkungsspalte als Validierungshinweis weitergeben
 
 ## Phase 5 - Validierung
 - [ ] T9: Source-Validierung implementieren
@@ -111,4 +111,4 @@ Projekt vollstaendig umsetzen: aus PS_PW.xlsx und Stellenbeschreibungen.xlsx mon
 8. T15 -> T16 -> T17
 
 ## Aktueller Startpunkt
-- [ ] Naechste aktive Aufgabe: T8 (Matching-Engine bauen)
+- [ ] Naechste aktive Aufgabe: T9 (Source-Validierung implementieren)

src/taetigkeitsnachweis/matcher.py

@@ -2,8 +2,11 @@
 
 from __future__ import annotations
 
+import re
+from typing import Any
+
 from .errors import ValidationError
-from .models import AllocationRecord
+from .models import AllocationRecord, MasterDataRecord, MatchedAssignment, ValidationIssue
 
 
 def calculate_foerderquote_percent(allocation: AllocationRecord, precision: int = 2) -> float:
@@ -14,3 +17,127 @@ def calculate_foerderquote_percent(allocation: AllocationRecord, precision: int
 
     raw_share = (allocation.funded_hours_weekly / allocation.contract_hours_weekly) * 100.0
     return round(raw_share, precision)
+
+
+def _normalize_name(name: str) -> str:
+    compact = re.sub(r"\s+", " ", name.strip())
+    return compact.casefold()
+
+
+def _with_tolerance(
+    value: float,
+    target: float,
+    tolerance: float,
+) -> bool:
+    return abs(value - target) <= tolerance
+
+
+def match_assignments(
+    allocation_records: list[AllocationRecord],
+    masterdata_records: list[MasterDataRecord],
+    config: dict[str, Any],
+) -> tuple[list[MatchedAssignment], list[ValidationIssue]]:
+    matching_cfg = config.get("matching", {})
+    tolerance = float(matching_cfg.get("share_tolerance_percent", 0.5))
+    prefer_function_hint = bool(matching_cfg.get("prefer_function_hint", True))
+
+    master_by_name: dict[str, list[MasterDataRecord]] = {}
+    for record in masterdata_records:
+        master_by_name.setdefault(_normalize_name(record.name), []).append(record)
+
+    matched: list[MatchedAssignment] = []
+    issues: list[ValidationIssue] = []
+
+    for allocation in allocation_records:
+        normalized_name = _normalize_name(allocation.employee_name)
+        candidates = master_by_name.get(normalized_name, [])
+        if not candidates:
+            issues.append(
+                ValidationIssue(
+                    code="MISSING_MASTERDATA",
+                    message=(
+                        f"No master-data match for employee '{allocation.employee_name}' "
+                        f"(project '{allocation.project_key}')."
+                    ),
+                    severity="error",
+                    context=allocation.employee_name,
+                )
+            )
+            continue
+
+        foerderquote = calculate_foerderquote_percent(allocation)
+        share_matches = [
+            candidate
+            for candidate in candidates
+            if _with_tolerance(candidate.stellenanteil_percent, foerderquote, tolerance)
+        ]
+
+        if len(share_matches) == 1:
+            selected = share_matches[0]
+        elif len(share_matches) > 1 and prefer_function_hint:
+            key = allocation.project_key.casefold()
+            hinted = [c for c in share_matches if key in c.funktion.casefold()]
+            if len(hinted) == 1:
+                selected = hinted[0]
+            else:
+                issues.append(
+                    ValidationIssue(
+                        code="AMBIGUOUS_MASTERDATA",
+                        message=(
+                            f"Ambiguous match for employee '{allocation.employee_name}' "
+                            f"(project '{allocation.project_key}', foerderquote {foerderquote:.2f}%)."
+                        ),
+                        severity="error",
+                        context=allocation.employee_name,
+                    )
+                )
+                continue
+        elif len(share_matches) > 1:
+            issues.append(
+                ValidationIssue(
+                    code="AMBIGUOUS_MASTERDATA",
+                    message=(
+                        f"Ambiguous match for employee '{allocation.employee_name}' "
+                        f"(project '{allocation.project_key}', foerderquote {foerderquote:.2f}%)."
+                    ),
+                    severity="error",
+                    context=allocation.employee_name,
+                )
+            )
+            continue
+        else:
+            issues.append(
+                ValidationIssue(
+                    code="NO_SHARE_MATCH",
+                    message=(
+                        f"No Stellenanteil match for employee '{allocation.employee_name}' "
+                        f"with foerderquote {foerderquote:.2f}% (project '{allocation.project_key}')."
+                    ),
+                    severity="error",
+                    context=allocation.employee_name,
+                )
+            )
+            continue
+
+        if allocation.notes:
+            issues.append(
+                ValidationIssue(
+                    code="ALLOCATION_NOTE",
+                    message=(
+                        f"Allocation note for '{allocation.employee_name}' / "
+                        f"'{allocation.project_key}': {allocation.notes}"
+                    ),
+                    severity="warning",
+                    context=allocation.employee_name,
+                )
+            )
+
+        matched.append(
+            MatchedAssignment(
+                allocation=allocation,
+                masterdata=selected,
+                foerderquote_percent=foerderquote,
+            )
+        )
+
+    return matched, issues