[Phase 3.1] Agent entity types + metadata structs (#47)

## Changes
- `crates/mem-core/src/entity.rs` — Added AgentPrompt, AgentSkill, AgentDecision to EntityType enum
- `crates/mem-core/src/agent_entity.rs` — New module (280 LOC): metadata structs, factories, stat updaters
- `crates/mem-core/src/lib.rs` — Module registration + exports

## Agent Entity Types
- **AgentPrompt**: template, target_model, task_category, usage_count, avg_quality, version
- **AgentSkill**: description, trigger_patterns, success_rate, invocation_count, avg_latency_ms
- **AgentDecision**: action, reasoning, alternatives, confidence, outcome (success/quality/feedback)

## Validation
- 8 new tests pass (factories, stats, round-trip, serialization)
- 174 total lib tests pass
- `cargo build --release` cleanReviewed-on: #47

Co-authored-by: rock <[email protected]>

.gitea/workflows/build.yaml

@@ -1,8 +1,11 @@
-name: PR Check
+name: CI
 
 on:
+  push:
+    branches: [main]
   pull_request:
     branches: [main]
+  workflow_dispatch:
 
 env:
   REGISTRY: forgejo.riotpiao.com
@@ -11,26 +14,28 @@ env:
   SQLX_OFFLINE: "true"
 
 jobs:
-  check:
+  ci:
-    name: Build, Test & Image
+    name: CI
     runs-on: rust
     steps:
-      - name: Install Docker
+      - name: Install Node.js and Docker
-        run: apt-get update && apt-get install -y docker.io
+        run: |
+          apt-get update
+          apt-get install -y nodejs docker.io
 
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Cargo build
+      - name: Cargo build all
         run: cargo build --all --verbose
 
-      - name: Cargo test
+      - name: Cargo test all
         run: cargo test --all --lib --verbose 2>&1 | tail -150 || true
 
       - name: Cargo clippy
         run: cargo clippy --all --all-targets -- -D warnings 2>&1 | tail -50 || true
 
-      - name: Clean build artifacts
+      - name: Clean build artifacts before Docker
         run: cargo clean
 
       - name: Get short SHA
@@ -45,7 +50,7 @@ jobs:
           REGISTRY_USER: ${{ secrets.FORGEJO_REGISTRY_USER }}
           REGISTRY_TOKEN: ${{ secrets.FORGEJO_REGISTRY_TOKEN }}
 
-      - name: Build and push image (SHA tag only)
+      - name: Build and push Docker image (SHA tag only)
         run: |
           docker build --no-cache --progress=plain \
             -t "${IMAGE}:${{ steps.sha.outputs.short_sha }}" \
@@ -53,5 +58,5 @@ jobs:
           docker push "${IMAGE}:${{ steps.sha.outputs.short_sha }}"
           echo "Pushed: ${IMAGE}:${{ steps.sha.outputs.short_sha }}"
 
-      - name: Prune images
+      - name: Prune unused images
         run: docker image prune -a --force 2>&1 | tail -3 || true