Development: Add AI enabled commit classifier (#44)

* feat: add commit classifier service for AI integration

* chore: update AI configuration

* fix: exclude AI services from openapi profile

* style: use explicit imports instead of wildcard

* feat: implement anomaly detection service and related DTOs

* feat: refactor AI DTOs and services for anomaly detection and commit classification

* feat: refactor anomaly and commit classification DTOs, update service logic for improved clarity

* feat: add prompt templates for anomaly detection and commit classification

* fix: improve confidence parsing logic in AnomalyDetectorService

* fix: clean up formatting in AnomalyDetectorService and CommitClassifierService, update AiResource documentation

* fix: remove baseUrl configuration from tsconfig.app.json

---------

Co-authored-by: Sindi Buklaji <ge43yif@mytum.de>
Co-authored-by: Predixx <liam.patrice.berger@gmail.com>
Co-authored-by: Liam Berger <63974342+Predixx@users.noreply.github.com>

Author: 3 people

docs/ai-anomaly-detection.md

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+# Anomaly Detection
+
+## Purpose
+Detects suspicious collaboration patterns in team commit history. **Does NOT affect CQI score** - only displays warning flags for instructor review.
+
+## Anomaly Types
+
+| Flag | Threshold | Meaning |
+|------|-----------|---------|
+| **LATE_DUMP** | >50% commits in last 20% of time | Cramming before deadline |
+| **SOLO_DEVELOPMENT** | One person >70% of commits | Unbalanced workload |
+| **INACTIVE_PERIOD** | Gap >50% of assignment period | Long period with no activity |
+| **UNEVEN_DISTRIBUTION** | LLM-detected | Commits in short bursts |
+
+## Detection Method
+**AI-first with validation:**
+1. **LLM** (GPT-4o-mini) - analyzes patterns, detects anomalies
+2. **Rule-based validation** - verifies findings with exact math, corrects percentages
+3. **Best of both** - LLM catches complex patterns, rules ensure accuracy
+
+## Testing
+
+**Endpoint:** `GET /api/ai/detect-anomalies?scenario={type}`
+
+### Test Scenarios
+
+**1. Late Dump + Solo Development (default)**
+```
+http://localhost:8080/api/ai/detect-anomalies
+```
+Expected: `[LATE_DUMP, SOLO_DEVELOPMENT]`
+- Alice: 7/8 commits (87.5%)
+- 650/800 lines in last 6 days (last 20% of 30-day period)
+
+**2. Solo Development Only**
+```
+http://localhost:8080/api/ai/detect-anomalies?scenario=solo
+```
+Expected: `[SOLO_DEVELOPMENT]`
+- Alice: 9/10 commits (90%)
+- Work spread throughout period
+
+**3. Inactive Period**
+```
+http://localhost:8080/api/ai/detect-anomalies?scenario=inactive
+```
+Expected: `[INACTIVE_PERIOD]`
+- 16-day gap between Day 6 and Day 22 (53% of 30-day period)
+- Balanced contributions otherwise
+
+**4. Good Collaboration**
+```
+http://localhost:8080/api/ai/detect-anomalies?scenario=good
+```
+Expected: `[]` (no anomalies)
+- Balanced: Alice 50%, Bob 50%
+- Spread evenly over time
+
+## Configuration
+
+```yaml
+harmonia:
+  ai:
+    enabled: true
+    anomaly-detector:
+      enabled: true
+      confidence-threshold: 0.7
+```
+
+## Example Output
+
+```json
+{
+  "flags": ["LATE_DUMP", "SOLO_DEVELOPMENT"],
+  "confidence": 1.0,
+  "reasons": [
+    "Alice has 83.3% of commits (5/6)",
+    "66.7% of commits (4/6) in last 2 days"
+  ]
+}
+```

src/main/java/de/tum/cit/aet/ai/dto/AnomalyDetectionRequestDTO.java

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+package de.tum.cit.aet.ai.dto;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import java.time.LocalDateTime;
+import java.util.List;
+
+/**
+ * Request for anomaly detection analysis.
+ *
+ * @param teamId team identifier
+ * @param commits list of commit summaries
+ * @param assignmentStart assignment start date
+ * @param assignmentEnd assignment end date (deadline)
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public record AnomalyDetectionRequestDTO(
+    String teamId,
+    List<CommitSummary> commits,
+    LocalDateTime assignmentStart,
+    LocalDateTime assignmentEnd
+) {
+    @JsonIgnoreProperties(ignoreUnknown = true)
+    public record CommitSummary(String author, LocalDateTime timestamp, int linesChanged) {}
+}

src/main/java/de/tum/cit/aet/ai/dto/AnomalyFlag.java

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+package de.tum.cit.aet.ai.dto;
+
+/**
+ * Anomaly flags for collaboration pattern detection.
+ */
+public enum AnomalyFlag {
+    /** More than 50% of commits in the last 20% of the assignment period. */
+    LATE_DUMP,
+    /** One person has more than 70% of all commits. */
+    SOLO_DEVELOPMENT,
+    /** Gap of more than 50% of the assignment period with no commits. */
+    INACTIVE_PERIOD,
+    /** Commits clustered in short bursts rather than spread out. */
+    UNEVEN_DISTRIBUTION
+}

src/main/java/de/tum/cit/aet/ai/dto/AnomalyReportDTO.java

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+package de.tum.cit.aet.ai.dto;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import java.util.List;
+
+/**
+ * Anomaly detection report.
+ *
+ * @param flags detected anomaly flags
+ * @param confidence overall confidence (0.0-1.0)
+ * @param reasons explanations for each detected anomaly
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public record AnomalyReportDTO(
+    List<AnomalyFlag> flags,
+    double confidence,
+    List<String> reasons
+) {
+}

src/main/java/de/tum/cit/aet/ai/dto/CommitClassificationDTO.java

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+package de.tum.cit.aet.ai.dto;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+
+/**
+ * Commit classification result.
+ *
+ * @param label the classification label
+ * @param confidence confidence score (0.0-1.0)
+ * @param reasoning explanation for the classification
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public record CommitClassificationDTO(
+    CommitLabel label,
+    double confidence,
+    String reasoning
+) {
+}

src/main/java/de/tum/cit/aet/ai/dto/CommitClassificationRequestDTO.java

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+package de.tum.cit.aet.ai.dto;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import java.util.List;
+
+@JsonIgnoreProperties(ignoreUnknown = true)
+public record CommitClassificationRequestDTO(
+    String sha,
+    String message,
+    List<String> filePaths,
+    String diffContent
+) {
+    public CommitClassificationRequestDTO(String sha, String message, List<String> filePaths) {
+        this(sha, message, filePaths, null);
+    }
+}

src/main/java/de/tum/cit/aet/ai/dto/CommitLabel.java

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+package de.tum.cit.aet.ai.dto;
+
+/**
+ * Labels for commit classification.
+ */
+public enum CommitLabel {
+    /** New functionality or significant enhancement. */
+    FEATURE,
+    /** Fixes a bug or error. */
+    BUG_FIX,
+    /** Adds or modifies tests only. */
+    TEST,
+    /** Code restructuring without behavior change. */
+    REFACTOR,
+    /** Formatting, comments, docs, whitespace, typos. */
+    TRIVIAL
+}